When using software compression and backing up virtual machines using SAN transport where does the compression take place?
Software compression is always done in the media server.
However typically backups that create IMG folders in the Disk Storage (such as Vmware Backup with GRT) will not do compession.
VMware backups should consolidate whitespace within the vmdk files so won't be the full size.
And you can performe VMware backups into DeDuplication Storage Folders which shoudl also save space.