JohnnyNeckU
Contributor
Contributor

DIsk consolidation vs deleting snapshots

Hi Guys,

We have a server with something like 9 snapshots all toke 9 months ago with a lot of change.

Performance isn't there anymore and we have the message saying disk consolidation for that vm is needed.

SO with that known, I'd like to know what are the step to follow?

If we want to delete all snapshots and consolidate the disks :

1- Should we consolidate before and delete snapshots after?

OR

2- Should we delete all snapshots and consolidate after?

OR

3- Consolidation will delete all snapshots in the process?

I'm a bit confused.

Thanks all!

5 Replies
a_p_
Leadership
Leadership

"Consolidate" and "Delete All" basically do the same thing, they both merge all deltas into the base disk. For details see http://kb.vmware.com/kb/2003638

André

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King_Robert
Hot Shot
Hot Shot

DELETE SNAPSHOT:

The snapshot files are consolidated and written to the parent snapshot disk and merge with the virtual machine base disk.

Deleting a snapshot leaves the current state of the virtual machine or any other snapshot untouched. Deleting a snapshot consolidates the changes between snapshots and previous disk states and writes to the parent disk all data from the delta disk that contains the information about the deleted snapshot. When you delete the base parent snapshot, all changes merge with the base virtual machine disk.

CONSOLIDATE SNAPSHOT:

Snapshot consolidation is useful when snapshot disks fail to compact after a Delete or Delete all operation or if the disk did not consolidate. This might happen, for example, if you delete a snapshot but its associated disk does not commit back to the base disk.

The snapshot Consolidation  searches for hierarchies or delta disks to combine without violating data dependency. After consolidation, redundant disks are removed, which improves virtual machine performance and saves storage space.

When initiating a snapshot delete action, the delta disk changes are then written to the base or parent VMDK file and the snapshot is deleted. With vSphere 5, a new option called consolidate was introduced. The purpose of consolidate is if the snapshot deletion process was not successful. In the past there were incidents where a user would initiate a snapshot deletion thinking the snapshot got deleted, yet to find out later that that’s not the case. With the consolidation option, when you initiate a snapshot deletion, if the snapshot fails to delete, the VM will then generate a warning letting you know that a consolidation is required. You would then run the snapshot consolidation option and the snapshot would get committed.   


JPM300
Commander
Commander

The most common case for consolidation of snapshots is when your backup software fails to delete/remove the snapshot properly.  As most backup software takes a snapshot of the VM and backs up the snapshot, the removeal process after sometimes fails.

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BigR
Contributor
Contributor

wish people would stop using the "delete" for what delete "all" does. it just confuses everyone more. delete(singular) just keeps the state where it was before the snapshot. DELETE ALL consolidates and removes but writes all changes to parent, all your changes are now there.. !

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continuum
Immortal
Immortal

> >delete(singular) just keeps the state where it was before the snapshot
Statements like this one are confusing: delete against a single snapshot merges the data into the parent. The action you describe is called "revert to snapshot"

Do you need support with a recovery problem ? - send a message via skype "sanbarrow"
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