I need to increase the size of a disk in one of my VM's, and I am running XSIBackup.
I am not allowed to change disk size as long as there are any snapshots. After running XSIBackup, there are snapshots.
How would I go about this?
Well, that depends on what --backup-prog you are using. Onediff will certainly need to keep its differential snapshot. In case of being using any other backup method, XSIBackup will not keep any snapshot of its own after the backup process has completed, but you may have some snapshots on your own.
Just inspect the snapshots in the VM, any XSIBackup snapshot will be easily identifiable and called xsibackupdiff.
In case you are using Onediff: delete any snapshot, stop the VM resize your disk and restart the Onediff cycle again. The drawback is that you will have to wait for the first full copy to be performed again.