This is a pretty normal question as its a bit odd. If you have purchased the StorNext FX Licenses for your non-mac machines then you need to fill out a form on the quantum website (http://www.quantum.com/serviceandsupport/license/stornext/index.aspx) this will generate you a license.dat file that you will need to put in /Library/Preferences/Xsan/
Make sure the license.dat file is on both MDC's
Then restart your volumes. You can fail from the primary MDC to the secondary MDC then back to primary.
now if you are in /Library/Preferences/Xsan/ and you do a "ls- la" in terminal you will see a file called .auth_secret
copy the .auth_secret file to "Windows C:\ProgramFIles\Stornext\config" on Linux "/usr/cvfs/config"
then you should be able to mount the volumes.
If you need further help feel free to reach out at me email@example.com
Only if you already have all of the required hardware for all computers does it make sense to implement Xsan. I'd even say you should have all of the recommended hardware also. Xsan requires a dedicated metadata server, fibre channel drops and switch for all computers, and Apple recommends a 2nd MDC server, and a private ethernet drop for all computers to talk to the MDCs.
Chances are you don't need a SAN but you haven't stated what the storage is going to be used for.