Question : Network home directory fail over

I have two apple Xserve systems that I want to connect to an Xraid via fiber with the Xsan application.  The purpose of the Xraid is to provide home directories and shared storage for our users.  The users do not have fiber connectivity to the xraid or the xserve systems.  

Here is my dilemma:

Current network home directory on the Xsan is something like this...
/Network/Servers/server1.mycompany.com/Volumes/SanVol/Users

Now if server1 failes, and server2 (standby controller) has to take over, how can I configure my users home directories so that they will be able to mount to server2 without having any impact on their current connections during the failover?

Answer : Network home directory fail over

Yes, IP Failover.

But Xsan is Apple's clustered filesystem for video workflows for example. It's not ideal for many *small* files like OS-level cache files, prefs files, etc. for user homes.

There is no convenient way to have both Xserves connect to the *same* Xserve-RAID. While you can use LUN masking that will separate things rather than provide access to the same RAID at the same time.

Besides which for Xsan, you *do* need another Xserve as the dedicated metadata controller and all of your clients *do* need fibre connection to the host (via fibre switches).
Better start at the beginning with that one: http://www.apple.com/xsan/

Otherwise, get a 2nd raid and syncronize the data between the two Xserve-RAIDs via rsync (many limitations  & potential pitfalls in 10.4) or something high-end and truly Mac-Native like ATempo Time Navigator provides high-powered synching (might be an add-on component). But that's not cheap (Enterprise backup software). There's also Synchronize Pro X or possibly BRU Clone, be sure to test those out and make sure they function according to need and expectation.

Then your IP Failover becomes a worthwhile pursuit.