Safe to delete snapshot?

[simon2016]

Hello All,

I've discovered an application based snapshot which was taken approximately one month a go. The size of the volume is 1Tb and has a single snapshot. If the deletion of the snapshot takes more than 12 hours is it likely to impact performance of the volume when users start work the following day? I read that the deletion process can be quite io intensive, could this affect access to other volumes?

On the same subject, does anyone have any information on the mechanics of how snapshots work? Is it comparable to how snapshots operate in VSphere?

Any advise/guidance appreciated.

Thanks 

[Stor_Mort]

Hi simon2016,

In older versions of LeftHand OS (before 11.5), snapshot deletion was an IO intensive background process. Multiple deletions could cause noticeable load during production hours. This is much less of a problem since 11.5.

Snapshots in LeftHand OS create additional 'layers' to a volume. The first snapshot is a complete thin-provisioned copy of the data blocks in a volume. Subsequent snapshots are deltas (incrementals) since the first snapshot. Mounting a delta creates a view which is the union of the previous snapshots. See chapter 13 of the StoreVirtual Users Guide.

[Stor_Mort]

Link to manuals:

www.hpe.com/support/storevirtualmanuals

[simon2016]

Thanks Stor_mort.

It looks like the snashot is safe to delete. It appears this snapshot is a complete thin provisioned copy of the original volume and won't affect access to the primary volume. I know in Vmware deleting a snapshot writes the changes back into the primary volume and so takes time to do this. This shouldn't be the case in Storevirtual.

Thanks again