reflect feedback and updated docs

docs/reference/operator_parameters.md

@@ -110,9 +110,10 @@ Those are top-level keys, containing both leaf keys and groups.
 
 * **min_instances**
   operator will run at least the number of instances for any given Postgres
-  cluster equal to the value of this parameter, except for standby clusters
-  which run with one pod if `numberOfInstances` is set to 1. When `-1` is
-  specified for `min_instances`, no limits are applied. The default is `-1`.
+  cluster equal to the value of this parameter. Standby clusters can still run
+  with `numberOfInstances: 1` as this is the [recommended setup](../user.md#setting-up-a-standby-cluster).
+  When `-1` is specified for `min_instances`, no limits are applied. The default
+  is `-1`.
 
 * **resync_period**
   period between consecutive sync requests. The default is `30m`.

docs/user.md

@@ -254,29 +254,22 @@ spec:
 
 ## How to clone an existing PostgreSQL cluster
 
-You can spin up a new cluster as a clone of the existing one, using a clone
+You can spin up a new cluster as a clone of the existing one, using a `clone`
 section in the spec. There are two options here:
 
-* Clone directly from a source cluster using `pg_basebackup`
-* Clone from an S3 bucket
+* Clone from an S3 bucket (recommended)
+* Clone directly from a source cluster
 
-### Clone directly
-
-```yaml
-spec:
-  clone:
-    cluster: "acid-batman"
-```
-
-Here `cluster` is a name of a source cluster that is going to be cloned. The
-cluster to clone is assumed to be running and the clone procedure invokes
-`pg_basebackup` from it. The operator will setup the cluster to be cloned to
-connect to the service of the source cluster by name (if the cluster is called
-test, then the connection string will look like host=test port=5432), which
-means that you can clone only from clusters within the same namespace.
+Note, that cloning can also be used for [major version upgrades](administrator.md#minor-and-major-version-upgrade)
+of PostgreSQL.
 
 ### Clone from S3
 
+Cloning from S3 has the advantage that there is no impact on your production
+database. A new Postgres cluster is created by restoring the data of another
+source cluster. If you create it in the same Kubernetes environment, use a
+different name.
+
 ```yaml
 spec:
   clone:
@@ -287,7 +280,8 @@ spec:
 
 Here `cluster` is a name of a source cluster that is going to be cloned. A new
 cluster will be cloned from S3, using the latest backup before the `timestamp`.
-In this case, `uid` field is also mandatory - operator will use it to find a
+Note, that a time zone is required for `timestamp` in the format of +00:00 which
+is UTC. The `uid` field is also mandatory. The operator will use it to find a
 correct key inside an S3 bucket. You can find this field in the metadata of the
 source cluster:
 
@@ -299,9 +293,6 @@ metadata:
   uid: efd12e58-5786-11e8-b5a7-06148230260c
 ```
 
-Note that timezone is required for `timestamp`. Otherwise, offset is relative
-to UTC, see [RFC 3339 section 5.6) 3339 section 5.6](https://www.ietf.org/rfc/rfc3339.txt).
-
 For non AWS S3 following settings can be set to support cloning from other S3
 implementations:
 
@@ -317,8 +308,22 @@ spec:
     s3_force_path_style: true
 ```
 
-Note, that cloning can also be used for [major version upgrades](administrator.md#minor-and-major-version-upgrade)
-of PostgreSQL.
+### Clone directly
+
+Another way to get a fresh copy of your source DB cluster is via basebackup. To
+use this feature simply leave out the timestamp field from the clone section.
+The operator will connect to the service of the source cluster by name. If the
+cluster is called test, then the connection string will look like host=test
+port=5432), which means that you can clone only from clusters within the same
+namespace.
+
+```yaml
+spec:
+  clone:
+    cluster: "acid-batman"
+```
+
+Be aware that on a busy source database this can result in an elevated load!
 
 ## Setting up a standby cluster
 

pkg/cluster/k8sres.go

@@ -1049,11 +1049,11 @@ func (c *Cluster) getNumberOfInstances(spec *acidv1.PostgresSpec) int32 {
 	newcur := cur
 
 	if spec.StandbyCluster != nil {
-		if newcur > 1 {
-			c.logger.Warningf("operator only supports standby clusters with 1 pod")
-		} else {
+		if newcur == 1 {
 			min = newcur
 			max = newcur
+		} else {
+			c.logger.Warningf("operator only supports standby clusters with 1 pod")
 		}
 	}
 	if max >= 0 && newcur > max {