On March 19, 2020 2:34:16 PM GMT+02:00, Rik Theys <Rik.Theys(a)esat.kuleuven.be&gt; wrote: > Hi, > > We are in the process of migrating our VM's from one storage domain to > another. Both domains are FC storage. > > There are VM's with thin provisioned disks of 16G that currently only > occupy 3G according to the interface. When we live migrate the disks > (with the VM running), I can see that a snapshot is being taken and > removed afterwards. > > After the storage migration, the occupied disk space on the new storage > domain is 6G. Even for a VM that hardly has any writes. How can I > reclaim this space? I've powered down the VM and did a sparsify on the > disk but this doesn't seem to have any effect. > > When I do a storage migration of a VM with a thin provisioned disk that > is down during the migration, the used disk space does not increase. > > VM's with fully allocated disks also don't seem to exhibit this > behavior. > > My storage domain now also contains VM with more occupied storage space > and the size of the disk?? There are no snapshots listed for those > disks. Is there a way to clean up this situation? > > Regards, > > Rik Are you sure that you zeroed out the empty space? I would enable the trim option for the VMs' disks, then run fstrim from the vm and last try to sparsify ?

If it's linux, you can do storage migration from the OS.

Best Regards, Strahil Nikolov