XServe G5 - Need to replace all three internal HDs - Hitachi Ultrastar OK?

There are several threads about drives which are known to work in the G5 Xserves but you'll have to search to see if those specific drives have been tested and reported by anyone. The G5 is pretty liberal about what it will accept although some people report having to jumper the speeds down because they shipped with an early version of the SATA spec and some newer faster ones have issues. The only drives I can personally vouch for are the Seagate Constellation ES 7200RPM SATA 2.0 drives. I put in a several 500GB and the worked immediately, I created RAID 1s and they've been humming along since then.

You're not limited to 500GB although I'm pretty sure you're limited to 2GB and maybe there are further limits on the 10.4 version of the OS. (I don't think so but it's been a long time so I can't be certain.) I only chose the 500GB because it was big enough (replacing 80GB drives) and I had to buy many so I went for the cost savings over the larger drives.

If you're really set on those drives and no one's reported on them you might consider getting one and testing it out before you commit to buying all of them. Otherwise opt for one of the reported known good drives and move on.

Good luck and report back with your results,

=Tod