gnt-instance modify -t drbd works from plain (on zfs)
[ganeti-extstorage-zfs] / sbin /
drwxr-xr-x   ..
-rwxr-xr-x 332 lvchange
-rwxr-xr-x 515 lvcreate
-rwxr-xr-x 273 lvrename
-rwxr-xr-x 1089 lvs
-rwxr-xr-x 453 pvs
-rwxr-xr-x 694 vgs