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Building on a previous question I had asked re: a VM freezing at the end of the backup, one of the solutions Veeam has offered is to make sure that there are no other snapshots that exist of that vm. After looking into it, I've found the following snapshot (presumably from a borked backup job) enter image description here

I would like to delete this snapshot in hopes of resolving my issue, however I need to ensure that the machine isn't negatively affected by this. Reading the VMWare documentation on the issue it states :

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.

Below is a picture of the datastore of the virtual machine (Datastore is DAS). If I schedule downtime for this server and shut it off during the process, can I safely delete this snapshot without any negative ramifications on the machine? I need to ensure that the state of the machine stays exactly how it is.

EDIT : For anyone interested this snapshot was successfully deleted last night without turning the machine off. It took about an hour and a half to consolidate the snapshot. After the snapshot was deleted, both snapshots mentioned by Jeff Hengesbach are no longer there.

enter image description here

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How do you think deleting this snapshot will affect your VM after you've read an official VmWare statement? What are the fears still? –  Danila Ladner Aug 9 '13 at 13:23
    
Well for starters the size of the snapshot (and only 77GB is available on the datastore) - I don't know if the size of the snapshot will cause an adverse reaction –  DKNUCKLES Aug 9 '13 at 13:26
    
Oh, yeah you need to make sure your datastore has more free space than provisioned space for that VM. Good point. –  Danila Ladner Aug 9 '13 at 13:28
    
In this case it doesn't however - a consultant did a P2V conversion for me a while ago and over-provisioned the machine. Hence my concern –  DKNUCKLES Aug 9 '13 at 13:34
    
Then you can't delete it. You need to expand your datastore first. –  Danila Ladner Aug 9 '13 at 13:38

1 Answer 1

up vote 1 down vote accepted

Deleting a snapshot can cause a performance impact to your storage layer, especially if there's a lot of writes to the guest during the process. If you can do it when it's powered off, there's no writes at all, obviously, so do that.

Regarding space : "From ESX4.0 Update 2 onwards, the snapshot mechanism has changed. VMware ESX now incorporates improved consolidation procedures which lessen the demand of free space. You are able to consolidate virtual machine delta disks even while minimal free space on your datastore is available."

http://kb.vmware.com/selfservice/documentLinkInt.do?micrositeID=&popup=true&languageId=&externalID=1015180

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Id o not think it applies for thin provisioned VMs. –  Danila Ladner Aug 9 '13 at 13:53
    
Please read the article I linked. It doesn't even mention thin provisioning, which has nothing to do with what we're talking about. –  mfinni Aug 9 '13 at 13:55
    
Right, sorry about that one it has nothing to do with that, my fault. I had the ticket open in this regard and they strongly recommended to have enough free datastore space to cover provisioned VM space to remove snapshot. And the ticket was open when I ran ESXi 5.0 Did you remove personally sizable snapshot on provisioned 500G VM with Datastore free space 50G? –  Danila Ladner Aug 9 '13 at 14:04
    
Here's a good description of the old behavior compared to the current behavior : yellow-bricks.com/2010/07/05/… –  mfinni Aug 9 '13 at 14:05
    
The base disk may grow somewhat if thin-provisioned, yes - and if DKNUCKLES has over-committed his disk, then that's a potential problem, and not only one related to snapshots. –  mfinni Aug 9 '13 at 14:07

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