I have a Sans Digital TowerRAID TR4UTBPN with 3 drives (2TB) setup as a RAID 5 volume for an effective 4 TB. I am wondering if it is possible to pull out the drives, put in fresh ones, set up a new volume, and when I want it, pull the new drives, put back the old ones, and recover the old volume. I read somewhere that at least some of Sans Digital's enclosures keep a copy of the volume data both in the hardware raid controller and on the drives, so that in principle it should be possible to tell the enclosure to use the drive data to reconstruct the volume. I don't know if the TR4UTBPN has that capability.
The RAID information is indeed stored on the drives; some of it is also in the controller memory - which goes away when you install a new set of drives.
It should be theoretically possible with nearly any RAID5 controller, the recovery procedure varies. I'd contact SANS Digital for the exact procedure. It may be fully automatic, i.e. the array will just come up when you re-install the old drive set; or you may have to execute a "read RAID data from drives" function first.
Systems Engineer DV411 - Los Angeles, CA