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A virtual machine snapshot is not a copy so it cannot be treated as a direct backup. A snapshot file is simply a log of changes to the original virtual disk. The virtual machine is running on the most current snapshot, not the original vmdk disk files. To reiterate: snapshots are not copies of the VM's original vmdk disk files. Taking a snapshot does not create a complete copy of the original vmdk disk file, rather it only copies the delta disks.
Side effects
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of running with snapshots
- An excessive number of decreased performance if there are too many delta files in a chain (caused by an excessive number of snapshots) or large delta files may cause decreased virtual machine and host performance. Not able to increase size of Virtual Diskhaving too many snapshots).
- decreased performance if delta files become too large.
- cannot increase Virtual Disk size while snapshots are active.
- Delta files can grow to the same size as the original base disk file, which is why the :
a virtual machine's provisioned storage size of a virtual machine increases by an amount up to the original size of the virtual machine multiplied by can grow to ( its original size ) multiplied by ( the number of snapshots on the virtual machine ).
Recommended Reading
- Understanding virtual machine snapshots in VMware ESXi and ESX (VMware KB Article 1015180)
- Best practices for virtual machine snapshots in the VMware environment (VMware KB Article 1025279)
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