On Fri, 12 Jul 2013, Tim Connors <tconnors@rather.puzzling.org> wrote:
Note that `mv <tank/subvol1>/blbah <tank/subvol2>/foo` to different subvols on the same device still copies-then-deletes the data as if its a separate filesystem (it is - think of it just like lvms) despite the fact that it's all just shared storage in the one pool. Slightly inconvenient and surprising, but makes sense in a way (even if zfs could be convinced to mark a set of blocks from a file as changing its owner from subvol1 to subvol2, how do you teach `mv` that this inter-mount move is special?
cp has the --reflink option, mv could use the same mechanism if it was supported across subvols. I believe that there is work on supporting reflink across subvols in BTRFS and there's no technical reason why ZFS couldn't do it too. -- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/