Bakbone NetVault, wich is recommended for Xsan use by Apple, is one.

http://www.bakbone.com/products/netvault_mac/

Another is Commvault Galaxy:

http://www.commvault.com/products.asp?pid=1

It's crtified for use with ADIC's Stornext on Windows 2003 server so it would defintly backup Xsan volumes.

You must need to offer Windows services to your SAN or LAN though to justify getting a Windows 2003 server w/Stornext, Commvault Galaxy and Windows CALs since it makes for an expensive proposition. So far, I've had one case where our client decided to go with Commvault on Windows 2003 in a hybrid broadcast SAN with Mac, Linux and Windows clients.

Bruno Forcier
Digital Video Specialist
Inso