Snapshot file size?

[njd62495]

OK I know this is a question that has probably been asked a thousand times but I'm still confused...

Lets say I have a 10 GB vmdk file that I have taken multiple snapshots. Snap1 is 3 GB, snap2 is 6GB and snap3 is 8 GB. I delete all the snapshots to merge them into the original vmdk.

Snap3 merges with snap2 growing snap2, snap2 them merges with 1 growing snap1 which finally merges with the original vmdk. I get that part, but am I now going to see a 17 GB vmdk file on the original

Or when 3 merges with 2 does it only merge the differences between the 2 delta files, and then 2 does the same with 1 which would grow the amount of space used on the vmdk but cannot grow the overall size of the original vmdk?

[weinstein5 · Accepted solution]

remember snapshots are recording changes to the base disk so when you consolidate the snapshots they will make the changes to the base disk and it will never grow larger than its stated size - in your example this would be 10 GB

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[jbogardus]

Another way to say it is that each snapshot file will contain versions of disk blocks that differ from the previous snapshot. When all snapshots are removed all those additional versions of each block of disk are removed and you are left with only one version of each block in the base disk ... which takes 10 GB of space for the 10 GB base disk. The version of each block that is retained may get taken from different delta files (since the latest version of one block may be in the base, while the latest of another in snap1 delta, and the latest of another in the snap2 delta) but still only one version of each block that makes up the 10 GBs will be kept.

[njd62495]

Thanks guys...for me that was always the flashing light in front of my face that I just couldnt see.