Update FAQ.md (#979 )

* Update FAQ.md * Update docs/faq.md Co-authored-by: Nikolay Edigaryev <edigaryev@gmail.com> --------- Co-authored-by: Nikolay Edigaryev <edigaryev@gmail.com>
Registry: limit the text output on unexpected status code (#981 )
2026-10-02 04:01:12 +02:00 · 2024-12-21 18:44:36 -10:00 · 2024-12-20 11:55:08 +04:00 · 2024-12-19 19:10:24 -10:00 · 2024-12-19 21:21:33 +04:00 · 2024-12-17 23:41:24 +04:00
22 changed files with 600 additions and 246 deletions
@@ -1,5 +1,5 @@
 {
-  "originHash" : "6a15657d8cb1d3e2b447f31aff5b47d6a9655d2262e48ca76476ba525435269b",
+  "originHash" : "22b3726bc4e4c6e9c04ac97cb08a82967feb39960a93d2909768a16e11576748",
  "pins" : [
    {
      "identity" : "antlr4",
@@ -55,15 +55,6 @@
        "version" : "1.5.0"
      }
    },
-    {
-      "identity" : "swift-async-algorithms",
-      "kind" : "remoteSourceControl",
-      "location" : "https://github.com/apple/swift-async-algorithms",
-      "state" : {
-        "branch" : "main",
-        "revision" : "5c8bd186f48c16af0775972700626f0b74588278"
-      }
-    },
    {
      "identity" : "swift-atomics",
      "kind" : "remoteSourceControl",
@@ -73,15 +64,6 @@
        "version" : "1.2.0"
      }
    },
-    {
-      "identity" : "swift-collections",
-      "kind" : "remoteSourceControl",
-      "location" : "https://github.com/apple/swift-collections.git",
-      "state" : {
-        "revision" : "9bf03ff58ce34478e66aaee630e491823326fd06",
-        "version" : "1.1.3"
-      }
-    },
    {
      "identity" : "swift-log",
      "kind" : "remoteSourceControl",
@@ -13,7 +13,6 @@ let package = Package(
    .package(url: "https://github.com/apple/swift-argument-parser", from: "1.3.1"),
    .package(url: "https://github.com/mhdhejazi/Dynamic", branch: "master"),
    .package(url: "https://github.com/apple/swift-algorithms", from: "1.2.0"),
-    .package(url: "https://github.com/apple/swift-async-algorithms", branch: "main"),
    .package(url: "https://github.com/malcommac/SwiftDate", from: "7.0.0"),
    .package(url: "https://github.com/antlr/antlr4", exact: "4.13.2"),
    .package(url: "https://github.com/apple/swift-atomics.git", .upToNextMajor(from: "1.2.0")),
@@ -29,7 +28,6 @@ let package = Package(
  targets: [
    .executableTarget(name: "tart", dependencies: [
      .product(name: "Algorithms", package: "swift-algorithms"),
-      .product(name: "AsyncAlgorithms", package: "swift-async-algorithms"),
      .product(name: "ArgumentParser", package: "swift-argument-parser"),
      .product(name: "Dynamic", package: "Dynamic"),
      .product(name: "SwiftDate", package: "SwiftDate"),
@@ -71,10 +71,14 @@ struct Clone: AsyncParsableCommand {

      try lock.unlock()

-      // APFS is doing copy-on-write so the above cloning operation (just copying files on disk)
+      // APFS is doing copy-on-write, so the above cloning operation (just copying files on disk)
      // is not actually claiming new space until the VM is started and it writes something to disk.
-      // So once we clone the VM let's try to claim a little bit of space for the VM to run.
-      try Prune.reclaimIfNeeded(UInt64(sourceVM.allocatedSizeBytes()), sourceVM)
+      //
+      // So, once we clone the VM let's try to claim the rest of space for the VM to run without errors.
+      let unallocatedBytes = try sourceVM.sizeBytes() - sourceVM.allocatedSizeBytes()
+      if unallocatedBytes > 0 {
+        try Prune.reclaimIfNeeded(UInt64(unallocatedBytes), sourceVM)
+      }
    }, onCancel: {
      try? FileManager.default.removeItem(at: tmpVMDir.baseURL)
    })
@@ -45,6 +45,23 @@ extension VZDiskImageSynchronizationMode {
  }
 }

+extension VZDiskImageCachingMode {
+  public init?(_ description: String) throws {
+    switch description {
+    case "automatic":
+      self = .automatic
+    case "cached":
+      self = .cached
+    case "uncached":
+      self = .uncached
+    case "":
+      return nil
+    default:
+      throw RuntimeError.VMConfigurationError("unsupported disk image caching mode: \"\(description)\"")
+    }
+  }
+}
+
 struct Run: AsyncParsableCommand {
  static var configuration = CommandConfiguration(abstract: "Run a VM")

@@ -176,7 +193,7 @@ struct Run: AsyncParsableCommand {
  @Flag(help: ArgumentHelp("Restrict network access to the host-only network"))
  var netHost: Bool = false

-  @Option(help: ArgumentHelp("Set the root disk options (e.g. --root-disk-opts=\"ro\" or --root-disk-opts=\"sync=none\")",
+  @Option(help: ArgumentHelp("Set the root disk options (e.g. --root-disk-opts=\"ro\" or --root-disk-opts=\"caching=cached,sync=none\")",
                             discussion: """
                             Options are comma-separated and are as follows:

@@ -187,6 +204,12 @@ struct Run: AsyncParsableCommand {
                             * sync=fsync — enable data synchronization with the permanent storage, but don't ensure that it was actually written (e.g. --root-disk-opts="sync=fsync")

                             * sync=full — enable data synchronization with the permanent storage and ensure that it was actually written (e.g. --root-disk-opts="sync=full")
+
+                             * caching=automatic — allows the virtualization framework to automatically determine whether to enable data caching
+
+                             * caching=cached — enabled data caching
+
+                             * caching=uncached — disables data caching
                             """, valueName: "options"))
  var rootDiskOpts: String = ""

@@ -308,7 +331,8 @@ struct Run: AsyncParsableCommand {
      nested: nested,
      audio: !noAudio,
      clipboard: !noClipboard,
-      sync: VZDiskImageSynchronizationMode(diskOptions.syncModeRaw)
+      sync: VZDiskImageSynchronizationMode(diskOptions.syncModeRaw),
+      caching: VZDiskImageCachingMode(diskOptions.cachingModeRaw)
    )

    let vncImpl: VNC? = try {
@@ -740,12 +764,12 @@ struct VMView: NSViewRepresentable {

    machineView.capturesSystemKeys = capturesSystemKeys

-    // Enable automatic display reconfiguration
-    // for guests that support it
+    // If not specified, enable automatic display
+    // reconfiguration for guests that support it
    //
    // This is disabled for Linux because of poor HiDPI
    // support, which manifests in fonts being too small
-    if #available(macOS 14.0, *), vm.config.os != .linux {
+    if #available(macOS 14.0, *), vm.config.displayRefit ?? (vm.config.os != .linux) {
      machineView.automaticallyReconfiguresDisplay = true
    }

@@ -761,12 +785,12 @@ struct AdditionalDisk {
  let configuration: VZStorageDeviceConfiguration

  init(parseFrom: String) throws {
-    let (diskPath, readOnly, syncModeRaw) = Self.parseOptions(parseFrom)
+    let (diskPath, readOnly, syncModeRaw, cachingModeRaw) = Self.parseOptions(parseFrom)

-    self.configuration = try Self.craft(diskPath, readOnly: readOnly, syncModeRaw: syncModeRaw)
+    self.configuration = try Self.craft(diskPath, readOnly: readOnly, syncModeRaw: syncModeRaw, cachingModeRaw: cachingModeRaw)
  }

-  static func craft(_ diskPath: String, readOnly diskReadOnly: Bool, syncModeRaw: String) throws -> VZStorageDeviceConfiguration {
+  static func craft(_ diskPath: String, readOnly diskReadOnly: Bool, syncModeRaw: String, cachingModeRaw: String) throws -> VZStorageDeviceConfiguration {
    let diskURL = URL(string: diskPath)

    if (["nbd", "nbds", "nbd+unix", "nbds+unix"].contains(diskURL?.scheme)) {
@@ -843,14 +867,14 @@ struct AdditionalDisk {
    let diskImageAttachment = try VZDiskImageStorageDeviceAttachment(
      url: diskFileURL,
      readOnly: diskReadOnly,
-      cachingMode: .automatic,
+      cachingMode: try VZDiskImageCachingMode(cachingModeRaw) ?? .automatic,
      synchronizationMode: try VZDiskImageSynchronizationMode(syncModeRaw)
    )

    return VZVirtioBlockDeviceConfiguration(attachment: diskImageAttachment)
  }

-  static func parseOptions(_ parseFrom: String) -> (String, Bool, String) {
+  static func parseOptions(_ parseFrom: String) -> (String, Bool, String, String) {
    var arguments = parseFrom.split(separator: ":")

    let options = DiskOptions(String(arguments.last!))
@@ -858,13 +882,14 @@ struct AdditionalDisk {
      arguments.removeLast()
    }

-    return (arguments.joined(separator: ":"), options.readOnly, options.syncModeRaw)
+    return (arguments.joined(separator: ":"), options.readOnly, options.syncModeRaw, options.cachingModeRaw)
  }
 }

 struct DiskOptions {
  var readOnly: Bool = false
  var syncModeRaw: String = ""
+  var cachingModeRaw: String = ""
  var foundAtLeastOneOption: Bool = false

  init(_ parseFrom: String) {
@@ -878,6 +903,9 @@ struct DiskOptions {
      case option.hasPrefix("sync="):
        self.syncModeRaw = String(option.dropFirst("sync=".count))
        self.foundAtLeastOneOption = true
+      case option.hasPrefix("caching="):
+        self.cachingModeRaw = String(option.dropFirst("caching=".count))
+        self.foundAtLeastOneOption = true
      default:
        continue
      }
@@ -17,6 +17,9 @@ struct Set: AsyncParsableCommand {
  @Option(help: "VM display resolution in a format of <width>x<height>. For example, 1200x800")
  var display: VMDisplayConfig?

+  @Flag(inversion: .prefixedNo, help: ArgumentHelp("Whether to automatically reconfigure the VM's display to fit the window"))
+  var displayRefit: Bool? = nil
+
  @Flag(help: ArgumentHelp("Generate a new random MAC address for the VM."))
  var randomMAC: Bool = false

@@ -63,6 +66,8 @@ struct Set: AsyncParsableCommand {
      }
    }

+    vmConfig.displayRefit = displayRefit
+
    if randomMAC {
      vmConfig.macAddress = VZMACAddress.randomLocallyAdministered()
    }
@@ -1,69 +1,6 @@
 import Foundation
-import AsyncAlgorithms

-fileprivate let urlSession = createURLSession()
-
-class DownloadDelegate: NSObject, URLSessionTaskDelegate {
-  let progress: Progress
-  init(_ progress: Progress) throws {
-    self.progress = progress
-  }
-
-  func urlSession(_ session: URLSession, didCreateTask task: URLSessionTask) {
-    self.progress.addChild(task.progress, withPendingUnitCount: self.progress.totalUnitCount)
-  }
-}
-
-class Fetcher {
-  static func fetch(_ request: URLRequest, viaFile: Bool = false, progress: Progress? = nil) async throws -> (AsyncThrowingChannel<Data, Error>, HTTPURLResponse) {
-    let delegate = progress != nil ? try DownloadDelegate(progress!) : nil
-
-    if viaFile {
-      return try await fetchViaFile(request, delegate: delegate)
-    }
-
-    return try await fetchViaMemory(request, delegate: delegate)
-  }
-
-  private static func fetchViaMemory(_ request: URLRequest, delegate: URLSessionTaskDelegate? = nil) async throws -> (AsyncThrowingChannel<Data, Error>, HTTPURLResponse) {
-    let dataCh = AsyncThrowingChannel<Data, Error>()
-
-    let (data, response) = try await urlSession.data(for: request, delegate: delegate)
-
-    Task {
-      await dataCh.send(data)
-
-      dataCh.finish()
-    }
-
-    return (dataCh, response as! HTTPURLResponse)
-  }
-
-  private static func fetchViaFile(_ request: URLRequest, delegate: URLSessionTaskDelegate? = nil) async throws -> (AsyncThrowingChannel<Data, Error>, HTTPURLResponse) {
-    let dataCh = AsyncThrowingChannel<Data, Error>()
-
-    let (fileURL, response) = try await urlSession.download(for: request, delegate: delegate)
-
-    // Acquire a handle to the downloaded file and then remove it.
-    //
-    // This keeps a working reference to that file, yet we don't
-    // have to deal with the cleanup any more.
-    let mappedFile = try Data(contentsOf: fileURL, options: [.alwaysMapped])
-    try FileManager.default.removeItem(at: fileURL)
-
-    Task {
-      for chunk in (0 ..< mappedFile.count).chunks(ofCount: 64 * 1024 * 1024) {
-        await dataCh.send(mappedFile.subdata(in: chunk))
-      }
-
-      dataCh.finish()
-    }
-
-    return (dataCh, response as! HTTPURLResponse)
-  }
-}
-
-fileprivate func createURLSession() -> URLSession {
+fileprivate var urlSession: URLSession = {
  let config = URLSessionConfiguration.default

  // Harbor expects a CSRF token to be present if the HTTP client
@@ -77,4 +14,84 @@ fileprivate func createURLSession() -> URLSession {
  config.httpShouldSetCookies = false

  return URLSession(configuration: config)
+}()
+
+class Fetcher {
+  static func fetch(_ request: URLRequest, viaFile: Bool = false) async throws -> (AsyncThrowingStream<Data, Error>, HTTPURLResponse) {
+    let task = urlSession.dataTask(with: request)
+
+    let delegate = Delegate()
+    task.delegate = delegate
+
+    let stream = AsyncThrowingStream<Data, Error> { continuation in
+      delegate.streamContinuation = continuation
+    }
+
+    let response = try await withCheckedThrowingContinuation { continuation in
+      delegate.responseContinuation = continuation
+      task.resume()
+    }
+
+    return (stream, response as! HTTPURLResponse)
+  }
+}
+
+fileprivate class Delegate: NSObject, URLSessionDataDelegate {
+  var responseContinuation: CheckedContinuation<URLResponse, Error>?
+  var streamContinuation: AsyncThrowingStream<Data, Error>.Continuation?
+
+  private var buffer: Data = Data()
+  private let bufferFlushSize = 16 * 1024 * 1024
+
+  func urlSession(
+    _ session: URLSession,
+    dataTask: URLSessionDataTask,
+    didReceive response: URLResponse,
+    completionHandler: @escaping (URLSession.ResponseDisposition) -> Void
+  ) {
+    // Soft-limit for the maximum buffer capacity
+    let capacity = min(response.expectedContentLength, Int64(bufferFlushSize))
+
+    // Pre-initialize buffer as we now know the capacity
+    buffer = Data(capacity: Int(capacity))
+
+    responseContinuation?.resume(returning: response)
+    responseContinuation = nil
+    completionHandler(.allow)
+  }
+
+  func urlSession(
+    _ session: URLSession,
+    dataTask: URLSessionDataTask,
+    didReceive data: Data
+  ) {
+    buffer.append(data)
+
+    if buffer.count >= bufferFlushSize {
+      streamContinuation?.yield(buffer)
+      buffer.removeAll(keepingCapacity: true)
+    }
+  }
+
+  func urlSession(
+    _ session: URLSession,
+    task: URLSessionTask,
+    didCompleteWithError error: Error?
+  ) {
+    if let error = error {
+      responseContinuation?.resume(throwing: error)
+      responseContinuation = nil
+
+      streamContinuation?.finish(throwing: error)
+      streamContinuation = nil
+    } else {
+      if !buffer.isEmpty {
+        streamContinuation?.yield(buffer)
+        buffer.removeAll(keepingCapacity: true)
+      }
+
+      streamContinuation?.finish()
+      streamContinuation = nil
+    }
+  }
 }
@@ -7,6 +7,21 @@ class DiskV2: Disk {
  private static let bufferSizeBytes = 4 * 1024 * 1024
  private static let layerLimitBytes = 512 * 1024 * 1024

+  // A zero chunk for faster than byte-by-byte comparisons
+  //
+  // Assumes that the other Data(...) is equal in size, but it's fine to get a false-negative
+  // on the last block since it costs only 4 MiB of excess data per 512 MiB layer.
+  //
+  // Some simple benchmarks ("sync && sudo purge" command was used to negate the disk caching effects):
+  // +--------------------------------------+---------------------------------------------------+
+  // | Operation                            | time(1) result                                    |
+  // +--------------------------------------+---------------------------------------------------+
+  // | Data(...) == zeroChunk               | 2.16s user 11.71s system 73% cpu 18.928 total     |
+  // | Data(...).contains(where: {$0 != 0}) | 603.68s user 12.97s system 99% cpu 10:22.85 total |
+  // +--------------------------------------+---------------------------------------------------+
+  private static let holeGranularityBytes = 4 * 1024 * 1024
+  private static let zeroChunk = Data(count: holeGranularityBytes)
+
  static func push(diskURL: URL, registry: Registry, chunkSizeMb: Int, concurrency: UInt, progress: Progress) async throws -> [OCIManifestLayer] {
    var pushedLayers: [(index: Int, pushedLayer: OCIManifestLayer)] = []

@@ -29,7 +44,7 @@ class DiskV2: Disk {
          let compressedData = try (data as NSData).compressed(using: .lz4) as Data
          let compressedDataDigest = Digest.hash(compressedData)

-          try await retry(maxAttempts: 5, backoff: .exponentialWithFullJitter(baseDelay: .seconds(5), maxDelay: .seconds(60))) {
+          try await retry(maxAttempts: 5) {
            if try await !registry.blobExists(compressedDataDigest) {
              _ = try await registry.pushBlob(fromData: compressedData, chunkSizeMb: chunkSizeMb, digest: compressedDataDigest)
            }
@@ -193,11 +208,26 @@ class DiskV2: Disk {
            diskWritingOffset = try zeroSkippingWrite(disk, rdisk, fsBlockSize, diskWritingOffset, data)
          }

-          try await registry.pullBlob(diskLayer.digest) { data in
-            try filter.write(data)
+          var rangeStart: Int64 = 0

-            // Update the progress
-            progress.completedUnitCount += Int64(data.count)
+          try await retry(maxAttempts: 5) {
+            try await registry.pullBlob(diskLayer.digest, rangeStart: rangeStart) { data in
+              try filter.write(data)
+
+              // Update the progress
+              progress.completedUnitCount += Int64(data.count)
+
+              // Update the current range start
+              rangeStart += Int64(data.count)
+            }
+          } recoverFromFailure: { error in
+            if error is URLError {
+              print("Error pulling disk layer \(index + 1): \"\(error.localizedDescription)\", attempting to re-try...")
+
+              return .retry
+            }
+
+            return .throw
          }

          try filter.finalize()
@@ -215,22 +245,6 @@ class DiskV2: Disk {
  }

  private static func zeroSkippingWrite(_ disk: FileHandle, _ rdisk: FileHandle?, _ fsBlockSize: UInt64, _ offset: UInt64, _ data: Data) throws -> UInt64 {
-    let holeGranularityBytes = 64 * 1024
-
-    // A zero chunk for faster than byte-by-byte comparisons
-    //
-    // Assumes that the other Data(...) is equal in size, but it's fine to get a false-negative
-    // on the last block since it costs only 64 KiB of excess data per 500 MB layer.
-    //
-    // Some simple benchmarks ("sync && sudo purge" command was used to negate the disk caching effects):
-    // +--------------------------------------+---------------------------------------------------+
-    // | Operation                            | time(1) result                                    |
-    // +--------------------------------------+---------------------------------------------------+
-    // | Data(...) == zeroChunk               | 2.16s user 11.71s system 73% cpu 18.928 total     |
-    // | Data(...).contains(where: {$0 != 0}) | 603.68s user 12.97s system 99% cpu 10:22.85 total |
-    // +--------------------------------------+---------------------------------------------------+
-    let zeroChunk = Data(count: holeGranularityBytes)
-
    var offset = offset

    for chunk in data.chunks(ofCount: holeGranularityBytes) {
@@ -1,6 +1,5 @@
 import Foundation
 import Algorithms
-import AsyncAlgorithms

 enum RegistryError: Error {
  case UnexpectedHTTPStatusCode(when: String, code: Int, details: String = "")
@@ -21,6 +20,7 @@ enum HTTPCode: Int {
  case Ok = 200
  case Created = 201
  case Accepted = 202
+  case PartialContent = 206
  case Unauthorized = 401
  case NotFound = 404
 }
@@ -29,14 +29,26 @@ extension Data {
  func asText() -> String {
    String(decoding: self, as: UTF8.self)
  }
+
+  func asTextPreview(limit: Int = 1000) -> String {
+    guard count > limit else {
+      return asText()
+    }
+
+    return "\(asText().prefix(limit))..."
+  }
 }

-extension AsyncThrowingChannel<Data, Error> {
-  func asData() async throws -> Data {
+extension AsyncThrowingStream<Data, Error> {
+  func asData(limitBytes: Int64? = nil) async throws -> Data {
    var result = Data()

    for try await chunk in self {
      result += chunk
+
+      if let limitBytes, result.count > limitBytes {
+        return result
+      }
    }

    return result
@@ -160,7 +172,7 @@ class Registry {
                                                 body: manifestJSON)
    if response.statusCode != HTTPCode.Created.rawValue {
      throw RegistryError.UnexpectedHTTPStatusCode(when: "pushing manifest", code: response.statusCode,
-                                                   details: data.asText())
+                                                   details: data.asTextPreview())
    }

    return Digest.hash(manifestJSON)
@@ -171,7 +183,7 @@ class Registry {
                                                 headers: ["Accept": ociManifestMediaType])
    if response.statusCode != HTTPCode.Ok.rawValue {
      throw RegistryError.UnexpectedHTTPStatusCode(when: "pulling manifest", code: response.statusCode,
-                                                   details: data.asText())
+                                                   details: data.asTextPreview())
    }

    let manifest = try OCIManifest(fromJSON: data)
@@ -197,7 +209,7 @@ class Registry {
                                                     headers: ["Content-Length": "0"])
    if postResponse.statusCode != HTTPCode.Accepted.rawValue {
      throw RegistryError.UnexpectedHTTPStatusCode(when: "pushing blob (POST)", code: postResponse.statusCode,
-                                                   details: data.asText())
+                                                   details: data.asTextPreview())
    }

    // Figure out where to upload the blob
@@ -218,7 +230,7 @@ class Registry {
      )
      if response.statusCode != HTTPCode.Created.rawValue {
        throw RegistryError.UnexpectedHTTPStatusCode(when: "pushing blob (PUT) to \(uploadLocation)",
-                                                     code: response.statusCode, details: data.asText())
+                                                     code: response.statusCode, details: data.asTextPreview())
      }
      return digest
    }
@@ -241,7 +253,7 @@ class Registry {
      // always accept both statuses since AWS ECR is not following specification
      if response.statusCode != HTTPCode.Created.rawValue && response.statusCode != HTTPCode.Accepted.rawValue {
        throw RegistryError.UnexpectedHTTPStatusCode(when: "streaming blob to \(uploadLocation)",
-                                                     code: response.statusCode, details: data.asText())
+                                                     code: response.statusCode, details: data.asTextPreview())
      }
      uploadedBytes += chunk.count
      // Update location for the next chunk
@@ -260,14 +272,26 @@ class Registry {
    case HTTPCode.NotFound.rawValue:
      return false
    default:
-      throw RegistryError.UnexpectedHTTPStatusCode(when: "checking blob", code: response.statusCode, details: data.asText())
+      throw RegistryError.UnexpectedHTTPStatusCode(when: "checking blob", code: response.statusCode, details: data.asTextPreview())
    }
  }

-  public func pullBlob(_ digest: String, handler: (Data) async throws -> Void) async throws {
-    let (channel, response) = try await channelRequest(.GET, endpointURL("\(namespace)/blobs/\(digest)"), viaFile: true)
-    if response.statusCode != HTTPCode.Ok.rawValue {
-      let body = try await channel.asData().asText()
+  public func pullBlob(_ digest: String, rangeStart: Int64 = 0, handler: (Data) async throws -> Void) async throws {
+    var expectedStatusCode = HTTPCode.Ok
+    var headers: [String: String] = [:]
+
+    // Send Range header and expect HTTP 206 in return
+    //
+    // However, do not send Range header at all when rangeStart is 0,
+    // because it makes no sense and we might get HTTP 200 in return
+    if rangeStart != 0 {
+      expectedStatusCode = HTTPCode.PartialContent
+      headers["Range"] = "bytes=\(rangeStart)-"
+    }
+
+    let (channel, response) = try await channelRequest(.GET, endpointURL("\(namespace)/blobs/\(digest)"), headers: headers, viaFile: true)
+    if response.statusCode != expectedStatusCode.rawValue {
+      let body = try await channel.asData(limitBytes: 4096).asTextPreview()
      throw RegistryError.UnexpectedHTTPStatusCode(when: "pulling blob", code: response.statusCode,
                                                   details: body)
    }
@@ -307,7 +331,7 @@ class Registry {
    body: Data? = nil,
    doAuth: Bool = true,
    viaFile: Bool = false
-  ) async throws -> (AsyncThrowingChannel<Data, Error>, HTTPURLResponse) {
+  ) async throws -> (AsyncThrowingStream<Data, Error>, HTTPURLResponse) {
    var urlComponents = urlComponents

    if urlComponents.queryItems == nil && !parameters.isEmpty {
@@ -330,7 +354,6 @@ class Registry {
    var (channel, response) = try await authAwareRequest(request: request, viaFile: viaFile, doAuth: doAuth)

    if doAuth && response.statusCode == HTTPCode.Unauthorized.rawValue {
-      _ = try await channel.asData()
      try await auth(response: response)
      (channel, response) = try await authAwareRequest(request: request, viaFile: viaFile, doAuth: doAuth)
    }
@@ -392,7 +415,7 @@ class Registry {
    let (data, response) = try await dataRequest(.GET, authenticateURL, headers: headers, doAuth: false)
    if response.statusCode != HTTPCode.Ok.rawValue {
      throw RegistryError.AuthFailed(why: "received unexpected HTTP status code \(response.statusCode) "
-        + "while retrieving an authentication token", details: data.asText())
+        + "while retrieving an authentication token", details: data.asTextPreview())
    }

    await authenticationKeeper.set(try TokenResponse.parse(fromData: data))
@@ -413,7 +436,7 @@ class Registry {
    return nil
  }

-  private func authAwareRequest(request: URLRequest, viaFile: Bool = false, doAuth: Bool) async throws -> (AsyncThrowingChannel<Data, Error>, HTTPURLResponse) {
+  private func authAwareRequest(request: URLRequest, viaFile: Bool = false, doAuth: Bool) async throws -> (AsyncThrowingStream<Data, Error>, HTTPURLResponse) {
    var request = request

    if doAuth {
@@ -38,7 +38,7 @@ struct UnsupportedHostOSError: Error, CustomStringConvertible {
        throw DecodingError.dataCorruptedError(forKey: .hardwareModel, in: container, debugDescription: "")
      }
      guard let hardwareModel = VZMacHardwareModel.init(dataRepresentation: data) else {
-        throw DecodingError.dataCorruptedError(forKey: .hardwareModel, in: container, debugDescription: "")
+        throw UnsupportedHostOSError()
      }
      self.hardwareModel = hardwareModel
    }
@@ -1,6 +1,5 @@
 import Foundation
 import Virtualization
-import AsyncAlgorithms
 import Semaphore

 struct UnsupportedRestoreImageError: Error {
@@ -50,7 +49,8 @@ class VM: NSObject, VZVirtualMachineDelegate, ObservableObject {
       nested: Bool = false,
       audio: Bool = true,
       clipboard: Bool = true,
-       sync: VZDiskImageSynchronizationMode = .full
+       sync: VZDiskImageSynchronizationMode = .full,
+       caching: VZDiskImageCachingMode? = nil
  ) throws {
    name = vmDir.name
    config = try VMConfig.init(fromURL: vmDir.configURL)
@@ -70,7 +70,8 @@ class VM: NSObject, VZVirtualMachineDelegate, ObservableObject {
                                                nested: nested,
                                                audio: audio,
                                                clipboard: clipboard,
-                                                sync: sync
+                                                sync: sync,
+                                                caching: caching
    )
    virtualMachine = VZVirtualMachine(configuration: configuration)

@@ -98,16 +99,13 @@ class VM: NSObject, VZVirtualMachineDelegate, ObservableObject {
    // Download the IPSW
    defaultLogger.appendNewLine("Fetching \(remoteURL.lastPathComponent)...")

-    let downloadProgress = Progress(totalUnitCount: 100)
-    ProgressObserver(downloadProgress).log(defaultLogger)
-
    let request = URLRequest(url: remoteURL)
-    let (channel, response) = try await Fetcher.fetch(request, viaFile: true, progress: downloadProgress)
+    let (channel, response) = try await Fetcher.fetch(request, viaFile: true)

    let temporaryLocation = try Config().tartTmpDir.appendingPathComponent(UUID().uuidString + ".ipsw")
-    defaultLogger.appendNewLine("Computing digest for \(temporaryLocation.path)...")
-    let digestProgress = Progress(totalUnitCount: response.expectedContentLength)
-    ProgressObserver(digestProgress).log(defaultLogger)
+
+    let progress = Progress(totalUnitCount: response.expectedContentLength)
+    ProgressObserver(progress).log(defaultLogger)

    FileManager.default.createFile(atPath: temporaryLocation.path, contents: nil)
    let lock = try FileLock(lockURL: temporaryLocation)
@@ -117,10 +115,9 @@ class VM: NSObject, VZVirtualMachineDelegate, ObservableObject {
    let digest = Digest()

    for try await chunk in channel {
-      let chunkAsData = Data(chunk)
-      fileHandle.write(chunkAsData)
-      digest.update(chunkAsData)
-      digestProgress.completedUnitCount += Int64(chunk.count)
+      fileHandle.write(chunk)
+      digest.update(chunk)
+      progress.completedUnitCount += Int64(chunk.count)
    }

    try fileHandle.close()
@@ -300,7 +297,8 @@ class VM: NSObject, VZVirtualMachineDelegate, ObservableObject {
    nested: Bool = false,
    audio: Bool = true,
    clipboard: Bool = true,
-    sync: VZDiskImageSynchronizationMode = .full
+    sync: VZDiskImageSynchronizationMode = .full,
+    caching: VZDiskImageCachingMode? = nil
  ) throws -> VZVirtualMachineConfiguration {
    let configuration = VZVirtualMachineConfiguration()

@@ -363,10 +361,15 @@ class VM: NSObject, VZVirtualMachineDelegate, ObservableObject {
    }

    // Storage
-    let attachment: VZDiskImageStorageDeviceAttachment = vmConfig.os == .linux ?
-      // Use "cached" caching mode for virtio drive to prevent fs corruption on linux
-      try VZDiskImageStorageDeviceAttachment(url: diskURL, readOnly: false, cachingMode: .cached, synchronizationMode: sync) :
-      try VZDiskImageStorageDeviceAttachment(url: diskURL, readOnly: false, cachingMode: .automatic, synchronizationMode: sync)
+    let attachment: VZDiskImageStorageDeviceAttachment =  try VZDiskImageStorageDeviceAttachment(
+      url: diskURL,
+      readOnly: false,
+      // When not specified, use "cached" caching mode for Linux VMs to prevent file-system corruption[1]
+      //
+      // [1]: https://github.com/cirruslabs/tart/pull/675
+      cachingMode: caching ?? (vmConfig.os == .linux ? .cached : .automatic),
+      synchronizationMode: sync
+    )

    var devices: [VZStorageDeviceConfiguration] = [VZVirtioBlockDeviceConfiguration(attachment: attachment)]
    devices.append(contentsOf: additionalStorageDevices)
@@ -24,6 +24,7 @@ enum CodingKeys: String, CodingKey {
  case memorySize
  case macAddress
  case display
+  case displayRefit

  // macOS-specific keys
  case ecid
@@ -52,6 +53,7 @@ struct VMConfig: Codable {
  private(set) var memorySize: UInt64
  var macAddress: VZMACAddress
  var display: VMDisplayConfig = VMDisplayConfig()
+  var displayRefit: Bool?

  init(
    platform: Platform,
@@ -121,6 +123,7 @@ struct VMConfig: Codable {
    self.macAddress = macAddress

    display = try container.decodeIfPresent(VMDisplayConfig.self, forKey: .display) ?? VMDisplayConfig()
+    displayRefit = try container.decodeIfPresent(Bool.self, forKey: .displayRefit)
  }

  func encode(to encoder: Encoder) throws {
@@ -136,6 +139,9 @@ struct VMConfig: Codable {
    try container.encode(memorySize, forKey: .memorySize)
    try container.encode(macAddress.string, forKey: .macAddress)
    try container.encode(display, forKey: .display)
+    if let displayRefit = displayRefit {
+      try container.encode(displayRefit, forKey: .displayRefit)
+    }
  }

  mutating func setCPU(cpuCount: Int) throws {
@@ -196,7 +196,7 @@ class VMStorageOCI: PrunableStorage {
      }

      try await withTaskCancellationHandler(operation: {
-        try await retry(maxAttempts: 5, backoff: .exponentialWithFullJitter(baseDelay: .seconds(5), maxDelay: .seconds(60))) {
+        try await retry(maxAttempts: 5) {
          // Choose the best base image which has the most deduplication ratio
          let localLayerCache = try await chooseLocalLayerCache(name, manifest, registry)

@@ -213,8 +213,7 @@ class VMStorageOCI: PrunableStorage {
          try await tmpVMDir.pullFromRegistry(registry: registry, manifest: manifest, concurrency: concurrency, localLayerCache: localLayerCache, deduplicate: deduplicate)
        } recoverFromFailure: { error in
          if error is URLError {
-            print("Error: \(error.localizedDescription)")
-            print("Attempting to re-try...")
+            print("Error pulling image: \"\(error.localizedDescription)\", attempting to re-try...")

            return .retry
          }
@@ -31,7 +31,7 @@ class RegistryRunner {

  init() async throws {
    // Start container
-    let container = try Self.dockerCmd("run", "-d", "--rm", "-p", "5000", "registry:2")
+    let container = try Self.dockerCmd("run", "-d", "--rm", "-p", "127.0.0.1:0:5000", "registry:2")
      .trimmingCharacters(in: CharacterSet.newlines)
    containerID = container

@@ -2,10 +2,18 @@

 Tart comes with a Golang-based benchmarking utility that allows one to easily compare host and guest performance.

-Currently, only Flexible I/O tester workloads are supported. To run them, [install Golang](https://go.dev/) and run the following command from this (`benchmark/`) directory:
+Currently, only Flexible I/O tester workloads are supported. To run them, first make sure that [passwordless sudo](https://serverfault.com/questions/160581/how-to-setup-passwordless-sudo-on-linux) is configured.
+
+Then, [install Golang](https://go.dev/). The easiest way is through [Homebrew](https://brew.sh/):

 ```shell
-go run cmd/main.go fio --image ghcr.io/cirruslabs/macos-sonoma-base:latest
+brew install go
+```
+
+Finally, run the following command from this (`benchmark/`) directory:
+
+```shell
+go run cmd/main.go fio --image ghcr.io/cirruslabs/macos-sonoma-base:latest --prepare 'sudo purge && sync'
 ```

 You can also enable the debugging output to diagnose issues:
@@ -16,6 +24,8 @@ go run cmd/main.go fio --debug

 ## Results

+### Mar 27, 2024
+
 Host:

 * Hardware: Mac mini (Apple M2 Pro, 8 performance and 4 efficiency cores, 32 GB RAM, `Mac14,12`)
@@ -37,3 +47,141 @@ Random writing of 100MB 	Tart    	2.0 GB/s 	493.31 kIOPS
 Random writing of 1000MB	local   	1.7 GB/s 	414.89 kIOPS  
 Random writing of 1000MB	Tart    	1.1 GB/s 	287.4 kIOPS  
 ```
+
+### Dec 2, 2024
+
+Host:
+
+* Hardware: MacBook Pro (Apple M1 Pro, 8 performance and 2 efficiency cores, 32 GB RAM, `MacBookPro18,3`)
+* OS: macOS Sequoia 15.1.1
+
+Guest:
+
+* Hardware: [Virtualization.Framework](https://developer.apple.com/documentation/virtualization)
+* OS: macOS Sonoma 14.6
+
+```
+Name                                    	Executor                                          	B/W (read)	B/W (write)	I/O (read) 	I/O (write) 	Latency (read)          	Latency (write)         	Latency (sync)      
+Single 4KiB random write process        	local                                             	0 B/s     	19 MB/s    	0 IOPS     	4.81 kIOPS  	0s ± 0s                 	203.418µs ± 155.865µs   	0s ± 0s             
+Single 4KiB random write process        	Tart                                              	0 B/s     	18 MB/s    	0 IOPS     	4.54 kIOPS  	0s ± 0s                 	213.655µs ± 188.822µs   	0s ± 0s             
+Single 4KiB random write process        	Tart (--root-disk-opts="sync=none")               	0 B/s     	19 MB/s    	0 IOPS     	4.68 kIOPS  	0s ± 0s                 	208.413µs ± 183.45µs    	0s ± 0s             
+Single 4KiB random write process        	Tart (--root-disk-opts="caching=cached")          	0 B/s     	24 MB/s    	0 IOPS     	6.11 kIOPS  	0s ± 0s                 	158.07µs ± 2.294654ms   	0s ± 0s             
+Single 4KiB random write process        	Tart (--root-disk-opts="sync=none,caching=cached")	0 B/s     	22 MB/s    	0 IOPS     	5.49 kIOPS  	0s ± 0s                 	173.414µs ± 310.213µs   	0s ± 0s             
+16 parallel 64KiB random write processes	local                                             	0 B/s     	18 GB/s    	0 IOPS     	273.76 kIOPS	0s ± 0s                 	323.423µs ± 604.999µs   	0s ± 0s             
+16 parallel 64KiB random write processes	Tart                                              	0 B/s     	16 GB/s    	0 IOPS     	273.48 kIOPS	0s ± 0s                 	335.086µs ± 7.591748ms  	0s ± 0s             
+16 parallel 64KiB random write processes	Tart (--root-disk-opts="sync=none")               	0 B/s     	18 GB/s    	0 IOPS     	281.49 kIOPS	0s ± 0s                 	326.655µs ± 7.485473ms  	0s ± 0s             
+16 parallel 64KiB random write processes	Tart (--root-disk-opts="caching=cached")          	0 B/s     	17 GB/s    	0 IOPS     	266.79 kIOPS	0s ± 0s                 	340µs ± 7.868384ms      	0s ± 0s             
+16 parallel 64KiB random write processes	Tart (--root-disk-opts="sync=none,caching=cached")	0 B/s     	16 GB/s    	0 IOPS     	251.02 kIOPS	0s ± 0s                 	355.077µs ± 8.354218ms  	0s ± 0s             
+Single 1MiB random write process        	local                                             	0 B/s     	1.3 GB/s   	0 IOPS     	1.31 kIOPS  	0s ± 0s                 	751.716µs ± 370.731µs   	0s ± 0s             
+Single 1MiB random write process        	Tart                                              	0 B/s     	1.1 GB/s   	0 IOPS     	1.1 kIOPS   	0s ± 0s                 	885.833µs ± 3.572539ms  	0s ± 0s             
+Single 1MiB random write process        	Tart (--root-disk-opts="sync=none")               	0 B/s     	1.1 GB/s   	0 IOPS     	1.08 kIOPS  	0s ± 0s                 	898.427µs ± 3.464261ms  	0s ± 0s             
+Single 1MiB random write process        	Tart (--root-disk-opts="caching=cached")          	0 B/s     	1000 MB/s  	0 IOPS     	976.47 IOPS 	0s ± 0s                 	972.491µs ± 6.87654ms   	0s ± 0s             
+Single 1MiB random write process        	Tart (--root-disk-opts="sync=none,caching=cached")	0 B/s     	1.1 GB/s   	0 IOPS     	1.03 kIOPS  	0s ± 0s                 	925.545µs ± 4.261693ms  	0s ± 0s             
+Random reads/writes (4k)                	local                                             	62 MB/s   	62 MB/s    	15.37 kIOPS	15.37 kIOPS 	2.059453ms ± 1.431822ms 	2.098761ms ± 1.445082ms 	0s ± 0s             
+Random reads/writes (4k)                	Tart                                              	38 MB/s   	38 MB/s    	9.6 kIOPS  	9.61 kIOPS  	3.30369ms ± 1.500464ms  	3.350589ms ± 1.512986ms 	0s ± 0s             
+Random reads/writes (4k)                	Tart (--root-disk-opts="sync=none")               	39 MB/s   	39 MB/s    	9.82 kIOPS 	9.83 kIOPS  	3.228106ms ± 1.367512ms 	3.27626ms ± 1.385964ms  	0s ± 0s             
+Random reads/writes (4k)                	Tart (--root-disk-opts="caching=cached")          	35 MB/s   	35 MB/s    	8.74 kIOPS 	8.76 kIOPS  	3.640772ms ± 15.472355ms	3.661779ms ± 15.264288ms	0s ± 0s             
+Random reads/writes (4k)                	Tart (--root-disk-opts="sync=none,caching=cached")	24 MB/s   	24 MB/s    	5.98 kIOPS 	5.99 kIOPS  	5.31188ms ± 4.55205ms   	5.375047ms ± 5.113847ms 	0s ± 0s             
+Random reads/writes (64k)               	local                                             	435 MB/s  	436 MB/s   	6.79 kIOPS 	6.8 kIOPS   	4.955892ms ± 2.066685ms 	4.440414ms ± 1.860036ms 	0s ± 0s             
+Random reads/writes (64k)               	Tart                                              	352 MB/s  	353 MB/s   	5.5 kIOPS  	5.51 kIOPS  	5.946067ms ± 2.041124ms 	5.658948ms ± 1.928372ms 	0s ± 0s             
+Random reads/writes (64k)               	Tart (--root-disk-opts="sync=none")               	331 MB/s  	332 MB/s   	5.16 kIOPS 	5.17 kIOPS  	6.330765ms ± 1.726782ms 	6.033862ms ± 1.671028ms 	0s ± 0s             
+Random reads/writes (64k)               	Tart (--root-disk-opts="caching=cached")          	428 MB/s  	428 MB/s   	6.68 kIOPS 	6.69 kIOPS  	4.661666ms ± 18.342779ms	4.904961ms ± 18.396772ms	0s ± 0s             
+Random reads/writes (64k)               	Tart (--root-disk-opts="sync=none,caching=cached")	297 MB/s  	298 MB/s   	4.64 kIOPS 	4.65 kIOPS  	6.591009ms ± 2.827053ms 	7.166883ms ± 3.001036ms 	0s ± 0s             
+sync test                               	local                                             	0 B/s     	48 MB/s    	0 IOPS     	21.15 kIOPS 	0s ± 0s                 	23.471µs ± 81.868µs     	23.374µs ± 6.255µs  
+sync test                               	Tart                                              	0 B/s     	24 MB/s    	0 IOPS     	10.72 kIOPS 	0s ± 0s                 	24.983µs ± 61.761µs     	67.575µs ± 76.196µs 
+sync test                               	Tart (--root-disk-opts="sync=none")               	0 B/s     	21 MB/s    	0 IOPS     	9.5 kIOPS   	0s ± 0s                 	26.973µs ± 63.935µs     	77.388µs ± 47.103µs 
+sync test                               	Tart (--root-disk-opts="caching=cached")          	0 B/s     	30 MB/s    	0 IOPS     	13.19 kIOPS 	0s ± 0s                 	11.923µs ± 25.225µs     	62.894µs ± 208.933µs
+sync test                               	Tart (--root-disk-opts="sync=none,caching=cached")	0 B/s     	38 MB/s    	0 IOPS     	17.02 kIOPS 	0s ± 0s                 	10.124µs ± 21.868µs     	47.803µs ± 33.706µs
+```
+
+### Dec 4, 2024
+
+Host:
+
+* AWS instance: `mac2.metal` + `gp3` EBS volume
+* Hardware: Mac mini (Apple M1, 4 performance and 4 efficiency cores, 16 GB RAM, `Macmini9,1`)
+* OS: macOS Sequoia 15.0
+
+Guest:
+
+* Hardware: [Virtualization.Framework](https://developer.apple.com/documentation/virtualization)
+* OS: macOS Sonoma 14.6
+
+```
+Name                                    	Executor                                          	B/W (read)	B/W (write)	I/O (read) 	I/O (write) 	Latency (read)            	Latency (write)           	Latency (sync)         
+Single 4KiB random write process        	local                                             	0 B/s     	4.4 MB/s   	0 IOPS     	1.1 kIOPS   	0s ± 0s                   	702.357µs ± 359.925µs     	0s ± 0s                
+Single 4KiB random write process        	Tart                                              	0 B/s     	2.6 MB/s   	0 IOPS     	656.37 IOPS 	0s ± 0s                   	1.140086ms ± 1.450472ms   	0s ± 0s                
+Single 4KiB random write process        	Tart (--root-disk-opts="sync=none")               	0 B/s     	2.7 MB/s   	0 IOPS     	677.07 IOPS 	0s ± 0s                   	1.179872ms ± 1.219626ms   	0s ± 0s                
+Single 4KiB random write process        	Tart (--root-disk-opts="caching=cached")          	0 B/s     	3.3 MB/s   	0 IOPS     	832.66 IOPS 	0s ± 0s                   	948.648µs ± 94.141338ms   	0s ± 0s                
+Single 4KiB random write process        	Tart (--root-disk-opts="sync=none,caching=cached")	0 B/s     	15 MB/s    	0 IOPS     	3.65 kIOPS  	0s ± 0s                   	260.717µs ± 19.977757ms   	0s ± 0s                
+16 parallel 64KiB random write processes	local                                             	0 B/s     	9.5 GB/s   	0 IOPS     	147.89 kIOPS	0s ± 0s                   	753.289µs ± 8.028974ms    	0s ± 0s                
+16 parallel 64KiB random write processes	Tart                                              	0 B/s     	10 GB/s    	0 IOPS     	176.96 kIOPS	0s ± 0s                   	429.83µs ± 33.792264ms    	0s ± 0s                
+16 parallel 64KiB random write processes	Tart (--root-disk-opts="sync=none")               	0 B/s     	12 GB/s    	0 IOPS     	180.89 kIOPS	0s ± 0s                   	383.524µs ± 17.524971ms   	0s ± 0s                
+16 parallel 64KiB random write processes	Tart (--root-disk-opts="caching=cached")          	0 B/s     	336 MB/s   	0 IOPS     	5.24 kIOPS  	0s ± 0s                   	9.970844ms ± 365.808663ms 	0s ± 0s                
+16 parallel 64KiB random write processes	Tart (--root-disk-opts="sync=none,caching=cached")	0 B/s     	9.4 GB/s   	0 IOPS     	147.04 kIOPS	0s ± 0s                   	524.139µs ± 34.100009ms   	0s ± 0s                
+Single 1MiB random write process        	local                                             	0 B/s     	178 MB/s   	0 IOPS     	173.36 IOPS 	0s ± 0s                   	3.835103ms ± 2.917977ms   	0s ± 0s                
+Single 1MiB random write process        	Tart                                              	0 B/s     	140 MB/s   	0 IOPS     	136.48 IOPS 	0s ± 0s                   	4.721178ms ± 7.744965ms   	0s ± 0s                
+Single 1MiB random write process        	Tart (--root-disk-opts="sync=none")               	0 B/s     	144 MB/s   	0 IOPS     	140.63 IOPS 	0s ± 0s                   	4.443507ms ± 11.572454ms  	0s ± 0s                
+Single 1MiB random write process        	Tart (--root-disk-opts="caching=cached")          	0 B/s     	47 MB/s    	0 IOPS     	45.55 IOPS  	0s ± 0s                   	13.267881ms ± 358.283094ms	0s ± 0s                
+Single 1MiB random write process        	Tart (--root-disk-opts="sync=none,caching=cached")	0 B/s     	196 MB/s   	0 IOPS     	191.4 IOPS  	0s ± 0s                   	4.102516ms ± 73.117503ms  	0s ± 0s                
+Random reads/writes (4k)                	local                                             	8.7 MB/s  	8.7 MB/s   	2.16 kIOPS 	2.16 kIOPS  	193.370794ms ± 42.593607ms	222.272016ms ± 56.586971ms	0s ± 0s                
+Random reads/writes (4k)                	Tart                                              	4.1 MB/s  	4.1 MB/s   	1.02 kIOPS 	1.03 kIOPS  	31.038867ms ± 13.508668ms 	31.184305ms ± 14.032766ms 	0s ± 0s                
+Random reads/writes (4k)                	Tart (--root-disk-opts="sync=none")               	4.2 MB/s  	4.2 MB/s   	1.04 kIOPS 	1.05 kIOPS  	30.368422ms ± 13.505627ms 	30.595412ms ± 13.840944ms 	0s ± 0s                
+Random reads/writes (4k)                	Tart (--root-disk-opts="caching=cached")          	2.2 MB/s  	2.2 MB/s   	545.33 IOPS	548.86 IOPS 	59.31316ms ± 716.351086ms 	57.647852ms ± 711.503882ms	0s ± 0s                
+Random reads/writes (4k)                	Tart (--root-disk-opts="sync=none,caching=cached")	6.0 MB/s  	6.0 MB/s   	1.5 kIOPS  	1.5 kIOPS   	21.244222ms ± 47.808399ms 	21.39459ms ± 44.716307ms  	0s ± 0s                
+Random reads/writes (64k)               	local                                             	121 MB/s  	121 MB/s   	1.89 kIOPS 	1.89 kIOPS  	61.894699ms ± 21.353345ms 	73.176462ms ± 13.02948ms  	0s ± 0s                
+Random reads/writes (64k)               	Tart                                              	72 MB/s   	72 MB/s    	1.12 kIOPS 	1.12 kIOPS  	27.842263ms ± 15.320781ms 	29.161858ms ± 15.765314ms 	0s ± 0s                
+Random reads/writes (64k)               	Tart (--root-disk-opts="sync=none")               	71 MB/s   	72 MB/s    	1.11 kIOPS 	1.11 kIOPS  	28.009493ms ± 16.333136ms 	29.285868ms ± 16.540589ms 	0s ± 0s                
+Random reads/writes (64k)               	Tart (--root-disk-opts="caching=cached")          	28 MB/s   	28 MB/s    	441.85 IOPS	444.81 IOPS 	71.726725ms ± 633.215756ms	72.597238ms ± 630.969305ms	0s ± 0s                
+Random reads/writes (64k)               	Tart (--root-disk-opts="sync=none,caching=cached")	81 MB/s   	81 MB/s    	1.26 kIOPS 	1.26 kIOPS  	24.872043ms ± 36.980111ms 	25.568559ms ± 37.027145ms 	0s ± 0s                
+sync test                               	local                                             	0 B/s     	1.9 MB/s   	0 IOPS     	868.08 IOPS 	0s ± 0s                   	92.08µs ± 233.598µs       	1.059033ms ± 98.751µs  
+sync test                               	Tart                                              	0 B/s     	1.5 MB/s   	0 IOPS     	649.42 IOPS 	0s ± 0s                   	146.737µs ± 434.261µs     	1.391898ms ± 699.148µs 
+sync test                               	Tart (--root-disk-opts="sync=none")               	0 B/s     	1.3 MB/s   	0 IOPS     	568.82 IOPS 	0s ± 0s                   	158.736µs ± 504.002µs     	1.59798ms ± 14.161331ms
+sync test                               	Tart (--root-disk-opts="caching=cached")          	0 B/s     	13 MB/s    	0 IOPS     	5.77 kIOPS  	0s ± 0s                   	26.596µs ± 832.169µs      	145.785µs ± 2.864048ms 
+sync test                               	Tart (--root-disk-opts="sync=none,caching=cached")	0 B/s     	19 MB/s    	0 IOPS     	8.37 kIOPS  	0s ± 0s                   	20.135µs ± 108.817µs      	98.274µs ± 239.631µs   
+```
+
+Host:
+
+* AWS instance: `mac2.metal` + `gp3` EBS volume
+* Hardware: Mac mini (Apple M1, 4 performance and 4 efficiency cores, 16 GB RAM, `Macmini9,1`)
+* OS: macOS Sequoia 15.0
+
+Guest:
+
+* Hardware: [Virtualization.Framework](https://developer.apple.com/documentation/virtualization)
+* OS: macOS Sequoia 15.1
+
+```
+Name                                    	Executor                                          	B/W (read)	B/W (write)	I/O (read) 	I/O (write) 	Latency (read)            	Latency (write)           	Latency (sync)         
+Single 4KiB random write process        	local                                             	0 B/s     	4.8 MB/s   	0 IOPS     	1.19 kIOPS  	0s ± 0s                   	690.818µs ± 326.595µs     	0s ± 0s                
+Single 4KiB random write process        	Tart                                              	0 B/s     	2.8 MB/s   	0 IOPS     	700.94 IOPS 	0s ± 0s                   	1.090362ms ± 918.444µs    	0s ± 0s                
+Single 4KiB random write process        	Tart (--root-disk-opts="sync=none")               	0 B/s     	3.0 MB/s   	0 IOPS     	746.23 IOPS 	0s ± 0s                   	1.028192ms ± 974.533µs    	0s ± 0s                
+Single 4KiB random write process        	Tart (--root-disk-opts="caching=cached")          	0 B/s     	4.2 MB/s   	0 IOPS     	1.04 kIOPS  	0s ± 0s                   	916.36µs ± 105.318323ms   	0s ± 0s                
+Single 4KiB random write process        	Tart (--root-disk-opts="sync=none,caching=cached")	0 B/s     	14 MB/s    	0 IOPS     	3.57 kIOPS  	0s ± 0s                   	269.796µs ± 22.419599ms   	0s ± 0s                
+16 parallel 64KiB random write processes	local                                             	0 B/s     	9.5 GB/s   	0 IOPS     	148.74 kIOPS	0s ± 0s                   	753.46µs ± 8.06509ms      	0s ± 0s                
+16 parallel 64KiB random write processes	Tart                                              	0 B/s     	5.2 GB/s   	0 IOPS     	81.46 kIOPS 	0s ± 0s                   	778.624µs ± 11.705178ms   	0s ± 0s                
+16 parallel 64KiB random write processes	Tart (--root-disk-opts="sync=none")               	0 B/s     	5.3 GB/s   	0 IOPS     	83.47 kIOPS 	0s ± 0s                   	865.448µs ± 38.369176ms   	0s ± 0s                
+16 parallel 64KiB random write processes	Tart (--root-disk-opts="caching=cached")          	0 B/s     	116 MB/s   	0 IOPS     	1.8 kIOPS   	0s ± 0s                   	37.601112ms ± 727.319309ms	0s ± 0s                
+16 parallel 64KiB random write processes	Tart (--root-disk-opts="sync=none,caching=cached")	0 B/s     	5.3 GB/s   	0 IOPS     	83.19 kIOPS 	0s ± 0s                   	900.751µs ± 51.223205ms   	0s ± 0s                
+Single 1MiB random write process        	local                                             	0 B/s     	177 MB/s   	0 IOPS     	173.27 IOPS 	0s ± 0s                   	3.833194ms ± 2.873871ms   	0s ± 0s                
+Single 1MiB random write process        	Tart                                              	0 B/s     	151 MB/s   	0 IOPS     	147.44 IOPS 	0s ± 0s                   	4.925853ms ± 7.793808ms   	0s ± 0s                
+Single 1MiB random write process        	Tart (--root-disk-opts="sync=none")               	0 B/s     	151 MB/s   	0 IOPS     	147.87 IOPS 	0s ± 0s                   	4.884797ms ± 7.563512ms   	0s ± 0s                
+Single 1MiB random write process        	Tart (--root-disk-opts="caching=cached")          	0 B/s     	72 MB/s    	0 IOPS     	69.9 IOPS   	0s ± 0s                   	8.909771ms ± 214.311644ms 	0s ± 0s                
+Single 1MiB random write process        	Tart (--root-disk-opts="sync=none,caching=cached")	0 B/s     	159 MB/s   	0 IOPS     	155.69 IOPS 	0s ± 0s                   	4.863448ms ± 88.965211ms  	0s ± 0s                
+Random reads/writes (4k)                	local                                             	8.7 MB/s  	8.7 MB/s   	2.16 kIOPS 	2.16 kIOPS  	193.353233ms ± 42.728494ms	222.325905ms ± 56.901372ms	0s ± 0s                
+Random reads/writes (4k)                	Tart                                              	3.5 MB/s  	3.5 MB/s   	862.89 IOPS	865.54 IOPS 	36.893229ms ± 12.644216ms 	37.143334ms ± 12.772017ms 	0s ± 0s                
+Random reads/writes (4k)                	Tart (--root-disk-opts="sync=none")               	3.6 MB/s  	3.6 MB/s   	907.4 IOPS 	911.55 IOPS 	35.048969ms ± 10.559354ms 	35.3046ms ± 10.67824ms    	0s ± 0s                
+Random reads/writes (4k)                	Tart (--root-disk-opts="caching=cached")          	2.7 MB/s  	2.8 MB/s   	684.11 IOPS	688.05 IOPS 	48.815322ms ± 687.806727ms	44.395556ms ± 635.532064ms	0s ± 0s                
+Random reads/writes (4k)                	Tart (--root-disk-opts="sync=none,caching=cached")	7.0 MB/s  	7.0 MB/s   	1.74 kIOPS 	1.74 kIOPS  	18.00448ms ± 93.784447ms  	18.617037ms ± 107.423001ms	0s ± 0s                
+Random reads/writes (64k)               	local                                             	121 MB/s  	121 MB/s   	1.89 kIOPS 	1.89 kIOPS  	61.983727ms ± 21.324782ms 	73.228597ms ± 12.730945ms 	0s ± 0s                
+Random reads/writes (64k)               	Tart                                              	75 MB/s   	75 MB/s    	1.17 kIOPS 	1.17 kIOPS  	26.830538ms ± 7.643051ms  	27.709602ms ± 7.830965ms  	0s ± 0s                
+Random reads/writes (64k)               	Tart (--root-disk-opts="sync=none")               	76 MB/s   	77 MB/s    	1.19 kIOPS 	1.19 kIOPS  	26.255337ms ± 7.302592ms  	27.256805ms ± 7.388266ms  	0s ± 0s                
+Random reads/writes (64k)               	Tart (--root-disk-opts="caching=cached")          	32 MB/s   	33 MB/s    	505.26 IOPS	508.66 IOPS 	65.170269ms ± 747.794957ms	61.062186ms ± 695.614904ms	0s ± 0s                
+Random reads/writes (64k)               	Tart (--root-disk-opts="sync=none,caching=cached")	79 MB/s   	79 MB/s    	1.23 kIOPS 	1.23 kIOPS  	25.861503ms ± 171.669777ms	25.992302ms ± 164.647788ms	0s ± 0s                
+sync test                               	local                                             	0 B/s     	1.9 MB/s   	0 IOPS     	865.16 IOPS 	0s ± 0s                   	100.95µs ± 268.722µs      	1.054051ms ± 365.377µs 
+sync test                               	Tart                                              	0 B/s     	1.6 MB/s   	0 IOPS     	704.13 IOPS 	0s ± 0s                   	133.886µs ± 390.263µs     	1.285085ms ± 575.27µs  
+sync test                               	Tart (--root-disk-opts="sync=none")               	0 B/s     	1.6 MB/s   	0 IOPS     	728.26 IOPS 	0s ± 0s                   	129.246µs ± 472.724µs     	1.242713ms ± 1.281286ms
+sync test                               	Tart (--root-disk-opts="caching=cached")          	0 B/s     	35 MB/s    	0 IOPS     	15.67 kIOPS 	0s ± 0s                   	11.319µs ± 24.771µs       	51.731µs ± 42.208µs    
+sync test                               	Tart (--root-disk-opts="sync=none,caching=cached")	0 B/s     	17 MB/s    	0 IOPS     	7.39 kIOPS  	0s ± 0s                   	21.23µs ± 81.749µs        	113.239µs ± 191.266µs  
+```
@@ -7,23 +7,63 @@ type Benchmark struct {

 var benchmarks = []Benchmark{
 	{
-		Name: "Random writing of 1MB",
-		Command: "fio --rw randwrite --runtime 30 --time_based --unlink 1 --output-format json " +
-			"--size 1MB --name unnamed --numjobs 1 --iodepth 1 --end_fsync 1",
+		// Ars Technica's "Single 4KiB random write process" test[1]
+		// with JSON output and created file cleanup
+		//
+		// [1]: https://arstechnica.com/gadgets/2020/02/how-fast-are-your-disks-find-out-the-open-source-way-with-fio/
+		Name: "Single 4KiB random write process",
+		Command: "fio --name=benchmark --ioengine=posixaio --rw=randwrite --bs=4k --size=4g --numjobs=1 --iodepth=1 --runtime=60 --time_based --end_fsync=1" +
+			" --output-format json --unlink 1",
 	},
 	{
-		Name: "Random writing of 10MB",
-		Command: "fio --rw randwrite --runtime 30 --time_based --unlink 1 --output-format json " +
-			"--size 10MB --name unnamed --numjobs 1 --iodepth 1 --end_fsync 1",
+		// Ars Technica's "16 parallel 64KiB random write processes" test[1]
+		// with JSON outpu, created file cleanup and group reporting (for
+		// easier analysis)
+		//
+		// [1]: https://arstechnica.com/gadgets/2020/02/how-fast-are-your-disks-find-out-the-open-source-way-with-fio/
+		Name: "16 parallel 64KiB random write processes",
+		Command: "fio --name=benchmark --ioengine=posixaio --rw=randwrite --bs=64k --size=256m --numjobs=16 --iodepth=16 --runtime=60 --time_based --end_fsync=1" +
+			" --output-format json --unlink 1 --group_reporting",
 	},
 	{
-		Name: "Random writing of 100MB",
-		Command: "fio --rw randwrite --runtime 30 --time_based --unlink 1 --output-format json " +
-			"--size 100MB --name unnamed --numjobs 1 --iodepth 1 --end_fsync 1",
+		// Ars Technica's "16 parallel 64KiB random write processes" test[1]
+		// with JSON output, created file cleanup and reduced file I/O size
+		// from 16 to 10 GB to avoid "No space left on device".
+		//
+		// [1]: https://arstechnica.com/gadgets/2020/02/how-fast-are-your-disks-find-out-the-open-source-way-with-fio/
+		Name: "Single 1MiB random write process",
+		Command: "fio --name=benchmark --ioengine=posixaio --rw=randwrite --bs=1m --size=10g --numjobs=1 --iodepth=1 --runtime=60 --time_based --end_fsync=1" +
+			" --output-format json --unlink 1",
 	},
 	{
-		Name: "Random writing of 1000MB",
-		Command: "fio --rw randwrite --runtime 30 --time_based --unlink 1 --output-format json " +
-			"--size 1000MB --name unnamed --numjobs 1 --iodepth 1 --end_fsync 1",
+		// Oracle's "Test random read/writes" (in IOPS Performance Tests[1]) category
+		// with JSON output, created file cleanup, without ETA newline, without custom
+		// file path, with file I/O size reduced from 500GB to 2GB to prevent
+		// "No space left on device" and with posixaio instead of libaio.
+		//
+		// [1]: https://docs.oracle.com/en-us/iaas/Content/Block/References/samplefiocommandslinux.htm#FIO_Commands
+		Name: "Random reads/writes (4k)",
+		Command: "fio --name=benchmark --size=2GB --direct=1 --rw=randrw --bs=4k --ioengine=posixaio --iodepth=256 --runtime=120 --numjobs=4 --time_based --group_reporting" +
+			" --output-format json --unlink 1",
+	},
+	{
+		// Oracle's "Test random read/writes" (in Throughput Performance Tests[1]) category
+		// with JSON output, created file cleanup, without ETA newline, without custom
+		// file path, with file I/O size reduced from 500GB to 2GB to prevent
+		// "No space left on device" and with posixaio instead of libaio.
+		//
+		// [1]: https://docs.oracle.com/en-us/iaas/Content/Block/References/samplefiocommandslinux.htm#Throughput_Performance_Tests
+		Name: "Random reads/writes (64k)",
+		Command: "fio --name=benchmark --size=2GB --direct=1 --rw=randrw --bs=64k --ioengine=posixaio --iodepth=64 --runtime=120 --numjobs=4 --time_based --group_reporting" +
+			" --output-format json --unlink 1",
+	},
+	{
+		// RedHat's "How can I test to see if my environment is fast enough for etcd"[1]
+		// with custom name
+		//
+		// [1]: https://access.redhat.com/solutions/5726511
+		Name: "sync test",
+		Command: "mkdir -p test-data && fio --name=benchmark --rw=write --ioengine=sync --fdatasync=1 --directory=test-data --size=22m --bs=2300" +
+			" --output-format json --unlink 1",
 	},
 }
@@ -1,21 +1,23 @@
 package fio

 import (
-	"context"
 	"encoding/json"
-	"errors"
 	"fmt"
-	"github.com/cirruslabs/tart/benchmark/internal/executor"
+	executorpkg "github.com/cirruslabs/tart/benchmark/internal/executor"
 	"github.com/cirruslabs/tart/benchmark/internal/executor/local"
 	"github.com/cirruslabs/tart/benchmark/internal/executor/tart"
 	"github.com/dustin/go-humanize"
 	"github.com/gosuri/uitable"
 	"github.com/spf13/cobra"
 	"go.uber.org/zap"
+	"go.uber.org/zap/zapio"
+	"os"
+	"os/exec"
 )

 var debug bool
 var image string
+var prepare string

 func NewCommand() *cobra.Command {
 	cmd := &cobra.Command{
@@ -26,6 +28,7 @@ func NewCommand() *cobra.Command {

 	cmd.Flags().BoolVar(&debug, "debug", false, "enable debug logging")
 	cmd.Flags().StringVar(&image, "image", "ghcr.io/cirruslabs/macos-sonoma-base:latest", "image to use for testing")
+	cmd.Flags().StringVar(&prepare, "prepare", "", "command to run before running each benchmark")

 	return cmd
 }
@@ -43,28 +46,95 @@ func run(cmd *cobra.Command, args []string) error {
 		_ = logger.Sync()
 	}()

-	executors, err := initializeExecutors(cmd.Context(), logger)
-	if err != nil {
-		return err
+	var executorInitializers = []struct {
+		Name string
+		Fn   func() (executorpkg.Executor, error)
+	}{
+		{
+			Name: "local",
+			Fn: func() (executorpkg.Executor, error) {
+				return local.New(logger)
+			},
+		},
+		{
+			Name: "Tart",
+			Fn: func() (executorpkg.Executor, error) {
+				return tart.New(cmd.Context(), image, nil, logger)
+			},
+		},
+		{
+			Name: "Tart (--root-disk-opts=\"sync=none\")",
+			Fn: func() (executorpkg.Executor, error) {
+				return tart.New(cmd.Context(), image, []string{
+					"--root-disk-opts",
+					"sync=none",
+				}, logger)
+			},
+		},
+		{
+			Name: "Tart (--root-disk-opts=\"caching=cached\")",
+			Fn: func() (executorpkg.Executor, error) {
+				return tart.New(cmd.Context(), image, []string{
+					"--root-disk-opts",
+					"caching=cached",
+				}, logger)
+			},
+		},
+		{
+			Name: "Tart (--root-disk-opts=\"sync=none,caching=cached\")",
+			Fn: func() (executorpkg.Executor, error) {
+				return tart.New(cmd.Context(), image, []string{
+					"--root-disk-opts",
+					"sync=none,caching=cached",
+				}, logger)
+			},
+		},
 	}
-	defer func() {
-		errs := []error{err}
-
-		for _, executor := range executors {
-			if err := executor.Close(); err != nil {
-				errs = append(errs, fmt.Errorf("failed to close executor %s: %w", executor.Name(), err))
-			}
-		}
-
-		err = errors.Join(errs...)
-	}()

 	table := uitable.New()
-	table.AddRow("Name", "Executor", "Bandwidth", "I/O operations")
+	table.AddRow("Name", "Executor", "B/W (read)", "B/W (write)", "I/O (read)", "I/O (write)",
+		"Latency (read)", "Latency (write)", "Latency (sync)")

 	for _, benchmark := range benchmarks {
-		for _, executor := range executors {
-			logger.Sugar().Infof("running benchmark %q on %s executor", benchmark.Name, executor.Name())
+		for _, executorInitializer := range executorInitializers {
+			if prepare != "" {
+				shell := "/bin/sh"
+
+				if shellFromEnv, ok := os.LookupEnv("SHELL"); ok {
+					shell = shellFromEnv
+				}
+
+				logger.Sugar().Infof("running prepare command %q using shell %q",
+					prepare, shell)
+
+				cmd := exec.CommandContext(cmd.Context(), shell, "-c", prepare)
+
+				loggerWriter := &zapio.Writer{Log: logger, Level: zap.DebugLevel}
+
+				cmd.Stdout = loggerWriter
+				cmd.Stderr = loggerWriter
+
+				if err := cmd.Run(); err != nil {
+					return fmt.Errorf("failed to run prepare command %q: %v", prepare, err)
+				}
+			}
+
+			logger.Sugar().Infof("initializing executor %s", executorInitializer.Name)
+
+			executor, err := executorInitializer.Fn()
+			if err != nil {
+				return err
+			}
+
+			logger.Sugar().Infof("installing Flexible I/O tester (fio) on executor %s",
+				executorInitializer.Name)
+
+			if _, err := executor.Run(cmd.Context(), "brew install fio"); err != nil {
+				return err
+			}
+
+			logger.Sugar().Infof("running benchmark %q on %s executor", benchmark.Name,
+				executorInitializer.Name)

 			stdout, err := executor.Run(cmd.Context(), benchmark.Command)
 			if err != nil {
@@ -84,12 +154,28 @@ func run(cmd *cobra.Command, args []string) error {

 			job := fioResult.Jobs[0]

+			readBandwidth := humanize.Bytes(uint64(job.Read.BW)*humanize.KByte) + "/s"
+			readIOPS := humanize.SIWithDigits(job.Read.IOPS, 2, "IOPS")
+
+			logger.Sugar().Infof("read bandwidth: %s, read IOPS: %s, read latency: %s",
+				readBandwidth, readIOPS, job.Read.LatencyNS.String())
+
 			writeBandwidth := humanize.Bytes(uint64(job.Write.BW)*humanize.KByte) + "/s"
 			writeIOPS := humanize.SIWithDigits(job.Write.IOPS, 2, "IOPS")

-			logger.Sugar().Infof("write bandwidth: %s, write IOPS: %s\n", writeBandwidth, writeIOPS)
+			logger.Sugar().Infof("write bandwidth: %s, write IOPS: %s, write latency: %s",
+				writeBandwidth, writeIOPS, job.Write.LatencyNS.String())

-			table.AddRow(benchmark.Name, executor.Name(), writeBandwidth, writeIOPS)
+			logger.Sugar().Infof("sync latency: %s", job.Sync.LatencyNS.String())
+
+			table.AddRow(benchmark.Name, executorInitializer.Name, readBandwidth, writeBandwidth,
+				readIOPS, writeIOPS, job.Read.LatencyNS.String(), job.Write.LatencyNS.String(),
+				job.Sync.LatencyNS.String())
+
+			if err := executor.Close(); err != nil {
+				return fmt.Errorf("failed to close executor %s: %w",
+					executorInitializer.Name, err)
+			}
 		}
 	}

@@ -97,37 +183,3 @@ func run(cmd *cobra.Command, args []string) error {

 	return nil
 }
-
-func initializeExecutors(ctx context.Context, logger *zap.Logger) ([]executor.Executor, error) {
-	var result []executor.Executor
-
-	logger.Info("initializing local executor")
-
-	local, err := local.New(logger)
-	if err != nil {
-		return nil, err
-	}
-	result = append(result, local)
-
-	logger.Info("local executor initialized")
-
-	logger.Info("initializing Tart executor")
-
-	tart, err := tart.New(ctx, image, logger)
-	if err != nil {
-		return nil, err
-	}
-	result = append(result, tart)
-
-	logger.Info("Tart executor initialized")
-
-	for _, executor := range result {
-		logger.Sugar().Infof("installing Flexible I/O tester (fio) on %s executor", executor.Name())
-
-		if _, err := executor.Run(ctx, "brew install fio"); err != nil {
-			return nil, err
-		}
-	}
-
-	return result, nil
-}
@@ -1,15 +1,35 @@
 package fio

+import (
+	"fmt"
+	"time"
+)
+
 type Result struct {
 	Jobs []Job `json:"jobs"`
 }

 type Job struct {
 	Name  string `json:"jobname"`
-	Write Write  `json:"write"`
+	Read  Stats  `json:"read"`
+	Write Stats  `json:"write"`
+	Sync  Stats  `json:"sync"`
 }

-type Write struct {
-	BW   float64 `json:"bw"`
-	IOPS float64 `json:"iops"`
+type Stats struct {
+	BW        float64 `json:"bw"`
+	IOPS      float64 `json:"iops"`
+	LatencyNS Latency `json:"lat_ns"`
+}
+
+type Latency struct {
+	Mean   float64 `json:"mean"`
+	Stddev float64 `json:"stddev"`
+}
+
+func (latency Latency) String() string {
+	meanDuration := time.Duration(latency.Mean) * time.Nanosecond
+	stddevDuration := time.Duration(latency.Stddev) * time.Nanosecond
+
+	return fmt.Sprintf("%v ± %v", meanDuration, stddevDuration)
 }
@@ -5,7 +5,6 @@ import (
 )

 type Executor interface {
-	Name() string
 	Run(ctx context.Context, command string) ([]byte, error)
 	Close() error
 }
@@ -8,7 +8,9 @@ import (
 	"github.com/avast/retry-go/v4"
 	"github.com/google/uuid"
 	"go.uber.org/zap"
+	"go.uber.org/zap/zapio"
 	"golang.org/x/crypto/ssh"
+	"io"
 	"net"
 	"strings"
 	"time"
@@ -21,7 +23,7 @@ type Tart struct {
 	logger      *zap.Logger
 }

-func New(ctx context.Context, image string, logger *zap.Logger) (*Tart, error) {
+func New(ctx context.Context, image string, runArgsExtra []string, logger *zap.Logger) (*Tart, error) {
 	tart := &Tart{
 		vmName: fmt.Sprintf("tart-benchmark-%s", uuid.NewString()),
 		logger: logger,
@@ -39,7 +41,11 @@ func New(ctx context.Context, image string, logger *zap.Logger) (*Tart, error) {
 	tart.vmRunCancel = vmRunCancel

 	go func() {
-		_ = Cmd(vmRunCtx, tart.logger, "run", "--no-graphics", tart.vmName)
+		runArgs := []string{"run", "--no-graphics", tart.vmName}
+
+		runArgs = append(runArgs, runArgsExtra...)
+
+		_ = Cmd(vmRunCtx, tart.logger, runArgs...)
 	}()

 	ip, err := CmdWithOutput(ctx, tart.logger, "ip", "--wait", "60", tart.vmName)
@@ -103,10 +109,12 @@ func (tart *Tart) Run(ctx context.Context, command string) ([]byte, error) {
 	}()
 	defer monitorCancel()

+	loggerWriter := &zapio.Writer{Log: tart.logger, Level: zap.DebugLevel}
 	stdoutBuf := &bytes.Buffer{}

 	sshSession.Stdin = bytes.NewBufferString(command)
-	sshSession.Stdout = stdoutBuf
+	sshSession.Stdout = io.MultiWriter(stdoutBuf, loggerWriter)
+	sshSession.Stderr = loggerWriter

 	if err := sshSession.Shell(); err != nil {
 		return nil, err
@@ -11,7 +11,7 @@ import (
 func TestTart(t *testing.T) {
 	ctx := context.Background()

-	tart, err := tart.New(ctx, "ghcr.io/cirruslabs/macos-sonoma-base:latest", zap.NewNop())
+	tart, err := tart.New(ctx, "ghcr.io/cirruslabs/macos-sonoma-base:latest", nil, zap.NewNop())
 	require.NoError(t, err)

 	output, err := tart.Run(ctx, "echo \"this is a test\"")
@@ -13,12 +13,12 @@ Remote images are pulled into `~/.tart/cache/OCIs/`.
 ## Nested virtualization support?

 Tart is limited by functionality of Apple's `Virtualization.Framework`. At the moment `Virtualization.Framework`
-doesn't support nested virtualization.
+supports nested virtualization only on M3 or M4 chips running macOS 15 (Sequoia). By default, it is disabled, but can be enabled by passing the `--nested` flag to `tart run`.

 ## Connecting to a service running on host

 To connect from within a virtual machine to a service running on the host machine
-please first make sure that the service is binded to `0.0.0.0`.
+please first make sure that the service is bound to `0.0.0.0`.

 Then from within a virtual machine you can access the service using the router's IP address that you can get either from `Preferences -> Network`
 or by running the following command in the Terminal:
@@ -29,7 +29,7 @@ netstat -nr | grep default | head -n 1 | awk '{print $2}'

 Note: that accessing host is only possible with the default NAT network. If you are running your virtual machines with
 [Softnet](https://github.com/cirruslabs/softnet) (via `tart run --net-softnet <VM NAME>)`, then the network isolation
-is stricter and it's not only possible to access the host.
+is stricter and it's not possible to access the host.

 ## Changing the default NAT subnet

@@ -57,7 +57,15 @@ This issue is worked around automatically [when using Softnet](http://github.com
 sudo defaults write /Library/Preferences/SystemConfiguration/com.apple.InternetSharing.default.plist bootpd -dict DHCPLeaseTimeSecs -int 600
 ```

-Note that this tweak persists across reboots, so normally you'll only need to do it once per new host.
+This tweak persists across reboots, so normally you'll only need to do it once per new host.
+
+If that doesn't help after starting a new VM, it's possible that the `/var/db/dhcpd_leases` file is already overfilled with 86,400-second leases. You can remove it with the following command and try starting a new VM again:
+
+```shell
+sudo rm /var/db/dhcpd_leases
+```
+
+And no worries, this file will be re-created on the next `tart run`.

 ## Running login/clone/pull/push commands over SSH

@@ -89,7 +97,7 @@ or features supported. If there is some feature missing please don't hesitate to
 Instead of Anka Registry, Tart can work with any OCI-compatible container registry. This provides a much more consistent
 and scalable experience for distributing virtual machines.

-Tart doesn't yet have an analogue of Anka Controller for managing long living VMs but [soon will be](https://github.com/cirruslabs/tart/issues/372).
+Tart does have an analogue of Anka Controller for managing VMs across a cluster of Mac hosts called [Orchard](orchard/quick-start.md).

 ## Automatic pruning

@@ -7,7 +7,7 @@ description: Use Packer to build custom VM images, configure VMs and work with r

 ## Creating from scratch

-Tart supports macOS and Linux virtual machines. All commands like `run` and `pull` work the same way regarding of the underlying OS a particular VM image has.
+Tart supports macOS and Linux virtual machines. All commands like `run` and `pull` work the same way regardless of the underlying OS a particular VM image has.
 The only difference is how such VM images are created. Please check sections below for [macOS](#creating-a-macos-vm-image-from-scratch) and [Linux](#creating-a-linux-vm-image-from-scratch) instructions.

 ### Creating a macOS VM image from scratch
Author	SHA1	Message	Date
Frederic BOLTZandNikolay Edigaryev	6dd43abf03	Update FAQ.md (#979 ) * Update FAQ.md * Update docs/faq.md Co-authored-by: Nikolay Edigaryev <edigaryev@gmail.com> --------- Co-authored-by: Nikolay Edigaryev <edigaryev@gmail.com>	2024-12-21 18:44:36 -10:00
Nikolay Edigaryev	04c6df2efb	Registry: limit the text output on unexpected status code (#981 ) * Registry: limit the text output on unexpected status code * pullBlob(): limit channel read-out on error to 4 KiB * No need to always read channel until end This was introduced in https://github.com/cirruslabs/tart/pull/284 because we were blocking in "urlSession(_ session: URLSession, dataTask: URLSessionDataTask, didReceive data: Data)", which we don't do anymore. * Fetcher.fetch(): remove "progress" argument as we don't need it anymore	2024-12-20 11:55:08 +04:00
Nikolay Edigaryev	5a8b48a392	Assorted documentation improvements (#982 )	2024-12-19 19:10:24 -10:00
Nikolay Edigaryev	b96ea087f5	tart pull: re-try disk layer downloads by specifying "Range" header (#980 )	2024-12-19 21:21:33 +04:00
Nikolay Edigaryev	eaec015edf	Fetcher: re-use URLSession (#976 ) Otherwise we start to periodically get RST's from GitHub, possibly because of too many connection opens, which has an effect of cancelling previously received bytes. These RST's can be observed in tcpdump/Wireshark or Console, emitted from the libusrtcp.dylib library, com.apple.network subsystem, for the Tart process: >tcp_input [C59.1.1.1:3] flags=[R] seq=1805021659, ack=0, win=0 state=CLOSED rcv_nxt=1805021659, snd_una=1752355607 You can also observe the "Received Bytes" in "Activity Monitor" for the Tart process while pulling ghcr.io/cirruslabs/macos-runner:sequoia, and this value will periodically decrease.	2024-12-17 23:41:24 +04:00
Nikolay Edigaryev	e27da23f4c	Fetcher: avoid response deadlock (#975 )	2024-12-17 01:19:06 +04:00
Nikolay Edigaryev	e6a30b07e3	clone: actually reclaim unallocated bytes (#974 )	2024-12-17 00:25:07 +04:00
Nikolay Edigaryev	2d7615bdf8	tart clone: only reclaim unallocated bytes (#973 )	2024-12-13 02:41:26 +04:00
Nikolay Edigaryev	31ab4218f7	tart pull: 284% faster pulls with default concurrency setting (#970 ) * DiskV2: avoid allocating zero chunk on each zeroSkippingWrite() call * Increase hole granularity size from 64 KiB to 4 MiB * Fetcher: never write to disk, thanks to URLSessionDataDelegate	2024-12-11 21:48:59 +04:00
Nikolay Edigaryev	32ebc5bdbc	New benchmark results on AWS mac2.metal for Sonoma and Sequoia guests (#965 ) * New benchmark results on AWS mac2.metal for Sonoma and Sequoia guests * Document the volume type used for EBS	2024-12-04 16:03:33 -05:00
Fedor Korotkov	c825ba4cb1	Better message if hardware model is not supported by the host (#962 ) Related to https://github.com/cirruslabs/tart/discussions/961 It seems `VZMacHardwareModel #init?(dataRepresentation: Data)` is nullable sometimes. Let's return a better message in this case.	2024-12-03 06:52:40 -05:00
Nikolay Edigaryev	2db3918930	Benchmark improvements (#960 ) * Get a fresh instance of executor for each benchmark invocation And don't pre-initialize all of the executors at once, as this might reach the maximum number of VMs limit in case we want to test multiple Tart executors. * Run benchmarks on Tart with different --root-disk-opts options * Fix TestTart * benchmark fio: introduce --prepare command-line argument To be able to specify --prepare='sudo purge && sync', similarly to Hyperfine[1]. [1]: https://github.com/sharkdp/hyperfine * Benchmark Tart with --root-disk-opts=caching=cached separately too * Add Ars Technica recommended benchmarks * Tart executor: log SSH session standard output and standard error * Reduce file I/O size from 16 to 10 GB to avoid "No space left on device" * Remove random writing tests to make space for more read/read-write tests * Add some "randrw"-style fio benchmarks * Show latency in benchmark results * Add sync benchmark and show read/write/sync latency * README.md: add new benchmark results	2024-12-03 00:26:26 +04:00
Nikolay Edigaryev	4256330f39	FAQ: document /var/db/dhcpd_leases and its removal (#957 )	2024-11-21 22:02:21 +04:00
Nikolay Edigaryev	0794edf15a	RegistryRunner: explicitly listen on localhost (#956 )	2024-11-21 09:24:37 -05:00
Nikolay Edigaryev	8536c16bcc	tart set: support --{,no-}display-auto-reconfigure (#954 ) * tart set: support --{,no-}display-auto-reconfigure * Remove extraneous spaces * displayAutoReconfigure → displayRefit	2024-11-20 23:55:11 +04:00
Nikolay Edigaryev	589d489782	tart run: support specifying disk caching mode (#953 )	2024-11-19 23:48:09 +04:00