Comments on: Delete all snapshots

By: Ruben

Ruben — Thu, 25 Feb 2010 21:54:53 +0000

Oinkmaster is right, the nicer way to remove several snapshots is to remove the nearest to the Base Disk repeatedly. This doesn’t require additional space.

If the Snapshot Manager displays no snapshots… then the problem begins.

On http://vmutils.blogspot.com/ you can find an script that will tell you in advance how much space the VM would need to ‘delete all’.

However, better than solve a problem is to prevent it.
http://www.youtube.com/watch?v=gl0VmmKNhYk

By: Steve

Steve — Mon, 14 Dec 2009 17:24:42 +0000

Ok, so I don’t necessarily agree with oinkmaster… My VMs tend to be quite complicated, I keep the system drive’s VMDK on one datastore, along with the config files. I then tend to have several additional VMDK files that I keep on different VMFS datastores.

Example, if the VM is a database, then I have a database LUN that is a lot faster and has more expensive technology at the SAN level, and then the logfiles have their own partition at the VM level, which is an additional VMFS datastore on what we call “medium” LUNs, which are kind of in between the LUNs where we keep the OS vs LUNs where we keep the Databases…

So when I snapshot, even though the VM is associated with several LUNs, the delta is always written to the LUN/VMFS datastore where the VM’s config files are located. I have never seen this documented and had to learn this on my own, and it is possible I am just incorrect/crazy

So yes, if your VM has a single VMDK file and the config files are stored on the same VMFS datastore, then Oinkmaster is correct, the space you use on the VMFS will probably not change much (although if the delta file contains say a delete command for half of the space, then I imagine when the snapshot is applied it would actually shrink the VMDK…?)

But, in more complex scenarios, like where I have snapshotted my database VM and the delta for the LOGS vmdk has been written to a different datastore (the datastore where the VM’s config files are) then deleting/applying the snapshot most definitely causes the VMDK file to grow. And it can grow a lot.

So in this case, you should not only be aware of the VMDK growing when you delete a snapshot, you also need to make sure that the VMFS datastore where the configs are located for that VM has enough free space to house the delta. Leaving a snapshot for too long can not only hose the VM, but it you are overprovisioned on your datastore (and with snapshots you may end up being overprovisioned and not know it) you really need to be aware of the free space left on the datastore that houses the config files for that particular VM.

By: Oinkmaster

Oinkmaster — Sat, 13 Jun 2009 20:21:04 +0000

If you just start by deleting the oldest snapshot then you need no additional storage at all. It then just gets merged in the original vmdk-file.

By: Duncan Epping

Duncan Epping — Wed, 13 May 2009 06:44:18 +0000

Correct, think twice before you start deleting… My Article wasn’t about solving a problem, it was about explaining what happens in the background. It’s the way it’s been designed.

By: lldmka

lldmka — Wed, 13 May 2009 05:39:27 +0000

The author probably assumed a certain level of intelligence in his readers.

By ‘think twice’ he clearly means to think about whether you have enough free space on the volume to commit the snapshots.

By: ESXi Snapshots not showing in VI Client « Virtual Andy

ESXi Snapshots not showing in VI Client « Virtual Andy — Fri, 24 Apr 2009 13:54:03 +0000

[...] it didn’t work. Now the machine won’t stay booted.I remembered reading something from Yellow-Bricks about disk space and snapshots. Oops. Since this VM was on an ESXi host, there was no service console commands to commit the [...]

By: Edoardo Fazzini

Edoardo Fazzini — Mon, 20 Apr 2009 12:15:12 +0000

By the way i remeber also that deleting snapshot process (committing changes) in VC console, viewed below in status bar, generate a timeout error when it arrives at 95%.
This is not a problem, because on side Host the process continue its works and finish after sometimes (it depends on how many GB are going to commit.. maybe hours..). So don’t worry!!! Be patient!!!

By: dbirnie

dbirnie — Sat, 28 Feb 2009 22:47:53 +0000

You know you IT types are so out of touch with reality.
The reasons for searching databases like yours is to recover from program defects.
If you don’t want to give an answer, stop posting.
How helpful is it to say “think twice”.

By: Find total disk usage of snapshots on a given LUN « Virtual Andy

Find total disk usage of snapshots on a given LUN « Virtual Andy — Sat, 03 Jan 2009 22:43:57 +0000

[...] some quick Googling, I found Delete all Snapshots which made me hold off on it until I had some more information about our snapshots. This number [...]

By: Be careful when using the delete all with snaps | Savage Nomads

Be careful when using the delete all with snaps | Savage Nomads — Sat, 28 Jun 2008 20:06:38 +0000

[...] Yellow Bricks has a good little write about problems you could run into if you use a lot of snaps then delete all snapshots. Make sure you have a lot of extra disk space when you do it. [...]