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Change and clarify wording

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erthalion 2018-06-06 17:36:21 +02:00
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@ -246,8 +246,8 @@ Note that timezone required for `timestamp` (offset relative to UTC, see RFC
## Increase volume size
PostgreSQL operator supports statefulset volume resize if you're using the
operator on top of AWS. For that you need to apply manifest with a new size,
and the operator will find out that a volume size needs to be changed:
operator on top of AWS. For that you need to change the size field of the
volume description in the cluster manifest and apply it:
```
apiVersion: "acid.zalan.do/v1"
@ -260,16 +260,22 @@ spec:
size: 5Gi # new volume size
```
You can only increase a volume size in this way, if a new requested size is
smaller than the previous one nothing will be done. After this update all the
new pods in a statefulset will be created with a new volume size. To increase a
volume size on already existing pods in a statefulset, the operator will
perform the following steps:
The operator compares the new value of the size field with the previous one and
acts on differences.
* modify EBS volume size
You can only enlarge the volume with the process described above, shrinking is
not supported and will emit a warning. After this update all the new volumes in
a statefulset are allocated according to the new size. To enlarge persistent
volumes attached to the running pods, the operator performs the following
actions:
* resize an actuall filesystem use `resize2fs`
* call AWS API to change the volume size
Note that if before a volume size was increased a statefulset was scaled down
and (after the change was applied) scaled back, those pods that were down will
have an old volume size, since a statefulset doesn't delete volumes.
* connect to the pod using `kubectl exec` and resize the filesystem with
`resize2fs`.
Fist step has a limitation, AWS rate-limits this operation to no more than once
every 6 hours.
Note that if the statefulset is scaled down before resizing the size changes
are only applied to the volumes attached to the running pods. The size of the
volumes that correspond to the previously running pods is not changed.