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xbradshr
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snapshot removal, delete versus delete all

I had a 50GB VM, with a 5GB snapshot. My intention was to remove the snapshot and commit changes to the base disk. I used the delete operation on the snapshot. It has done as a wanted, but the base disk is 55GB. I was surprised on the size increase, as I expected the disks to merge. There is around 25GB of free space on the Windows guest. Disk is thick provisioned. ESXI 5.5 with the latest patches.

On reading up, should i have used delete all, or does it not matter? I was not expecting the base disk size to increase, but maybe i am misunderstanding how snapshots work. I am not particularly bothered by 5GB, but just wanted to ensure i understand what would happen in a much larger scenario.

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a_p_
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Whether a thin provisioned virtual disk file increases when deleting a snapshot depends on the data in the snapshot. It's the guest OS which places its data on specific locations within its disk/partition. Data blocks which were previously in use (i.e. already allocated in the base .vmdk file) will be overwritten, others will be appended to the base .vmdk file. If - as in your case - the base disk increases by the size of the snapshot, it seems that the guest OS wrote data to locations on the disk which have not been used before.

André

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a_p_
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Whether a thin provisioned virtual disk file increases when deleting a snapshot depends on the data in the snapshot. It's the guest OS which places its data on specific locations within its disk/partition. Data blocks which were previously in use (i.e. already allocated in the base .vmdk file) will be overwritten, others will be appended to the base .vmdk file. If - as in your case - the base disk increases by the size of the snapshot, it seems that the guest OS wrote data to locations on the disk which have not been used before.

André

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