Another snapshot / snapclone question

[GilchristT]

While we're asking about Snapshots on the EVA...

Is there any way of making the snapshot / snapclone the active volume in the EVA4/6/8K range?

For example if I had taken a snapshot of my Exchange Database and Log volumes, then they got corrupted would I have to mount the snapshots as new volumes and manually copy the data across?

I'm working in a purely WinTel environment.

thanks

tommy

[Nigel Poulton]

Hi Tommy,

When a snapclone is created it automatically becomes the active member of its own disk "family", and only an active member of a disk family can be presented to a host.

A snapshot on the other hand not the active member of a disk family and therefore not availble to be rpesented to a host.

Mackem

[Uwe Zessin]

A snapshot can definitely presented to a host.

There are some things to keep in mind:
- it is not always advisable to present a snapshot/snapclone to the same host, because the snap is a block-for-block copy which has the same metadata (e.g. signature)

- when you copy the data from the snapshot to the original volume you cause lots of copy-out operations which can make the snapshot very large, up to 100% of the original disk. This is because you are overwriting the old blocks, but the snapshot must keep its point-in-time view.

[Matt Burgess]

Hi Tommy,
Snapclone - yes. This is what they are for.

Snapshot - yes, but it really only should be considered a temporary fix. Reasons:

1. If you have a snapshot you can never delete the original.

2. You can't take a snap of a snap; if the snap becomes the production disk then you can never snap your data again.

3. Performance (cache+copy out).

If you want to have this capability I would suggest using snapclones for this purpose.