Monday, May 18, 2015

VMWare snapshot management

Before testing several configurations on my new brand FreeNAS server hosted on VMWare ESXi 6.0, I took a snapshot. Then run tests. The FreeNAS is composed by two virtual disks : one for the software is 20Gb, one for the data is 900Gb.
After a while, bouncing the FreeNAS guest ended in error, VMWare is complaining about disk space not enough…
No way to start it up again.

Quite surprising. Except if we know that snapshots keep increasing while the VM is running. In fact, the snapshot keep all the logs to redo the difference made. Since the data virtual disk is big, after quite some time the snapshots can fill up all your physical disk hosting the VM.
The straightaway solution is to drop the snapshots.

Subsequent solution : hosting snapshot in a much larger disk array (datastore) – by default it is hosted where the virtual disk is sitting.
For the sake, here we go :
Creating snapshots in a different location than default virtual machine directory for VMware ESXi and VMware ESX
To make it short, stop the VM, add the following lines in .vmx file of the VM, and restart :
workingDir = "new_path_location"
snapshot.redoNotWithParent = "true"

Lesson learned.

Nicolas.

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