XServe IP Failover not quite Universal yet
It may not be the most-used feature of Apple's XServe, but IP Failover -- the ability of a standby server to take over the IP address and service responsibilities of a failed primary box -- is vital in enhanced-availability setups and one of the "marquee" qualifications for the use of Apple's iron in BigCorp server rooms. With OS X Server's support for FireWire networking, you can use a single 6-pin FW cable between the two servers as the private 'heartbeat' network that lets the understudy know when the leading lady has slipped on the stairs, so to speak.
Unfortunately, as Ars Technica and MacFixit have explicated (based on a recent Knowledge Base article), there's a problem or two: not only is mixing G5 and Intel XServes in a failover configuration currently verboten, the failover tools don't work on any of Apple's Intel-based hardware. Drat! We can only hope that this is fixed before Leopard Server comes along.
