So Lion generally represented a pretty serious move toward 64-bit systems for Mac OS X. But while I was poking around the Lion Server: Advanced Administration guidelines here:
I ran across this gem:
If you are trying to submit jobs over 2 GB The Xgrid controller is a 32-bit process and keeps most job input and output data in memory. This means that the controller can crash if your jobs require a large amount of input or produce a large amount of output.
You can use a shared filesystem (such as Xsan or NFS) to share large amounts of data between distributed processes.
Is that text a holdover from an older version of the documentation, or is the Xgrid controller still really a 32-bit process?