This is expected behavior.
The upgrade from Xsan 1.x to Xsan 2.x involves modifying the Xsan filesystem. The time needed for this procedure depends on the number of files on the volume. During this volume modification, Xsan Admin is not able to control or present statistics relating to the volume.
To verify that the volume modification is underway, open the volume's log (located at /Library/Filesystems/Xsan/data/XsanVolumeName/cvlog). If the update is underway, the last log entries will resemble this:
fsm[6334]: RPL_init: RPL upgrade required.
fsm[6334]: RPL_Upgrade: Removing existing RPL attributes.
fsm[6334]: RPL_Upgrade: removal completed 11 blocks
...
fsm[6334]: RPL_Upgrade: removal completed 8400 blocks
fsm[6334]: RPL_Upgrade: RPL removal complete. Repopulating...
fsm[6334]: RPL_Upgrade: 1% complete (1 of 8400 IEL blocks)
...
fsm[6334]: RPL_Upgrade: 100% complete (8400 of 8400 IEL blocks)
fsm[6334]: RPL_init: RPL upgrade complete.