Pros: Ready to run. True headless booting. Unlimited licenses for Windows, Mac, and NFS file sharing clients. 12 1,066MHz DDR3 DIMM sockets leverage Nehalem's triple-channel on-chip RAM controller. Independent system management controller ('lights out management') with GUI, SNMP, and IPMI 2.0 support. Optional integrated hardware RAID controller with battery-backed RAM cache.
Cons: Lights-out management controller lacks KVM over IP support; no official serial over LAN support. Proprietary drive trays are not user-upgradeable with raw drives.
The lack of power controls is a shame because no x86 server is better equipped to make smart decisions about power than Xserve. The temperature, voltage, and current draw of most major components are tracked continuously and reported to Xserve's independent system management controller, which Apple calls the "LOM," for "lights-out management." LOM data is readable with Apple's Server Monitor GUI or the ipmitool command-line utility. The LOM shares one of Xserve's two gigabit Ethernet ports, using its own IP address and security credentials.
Xserve's LOM is limited in comparison to other servers' baseboard management controllers. When the system is powered down, it functions primarily as a remote power switch and a means to select the source of the boot image. The LOM lacks the ability to remotely control the console (KVM over IP), although ipmitool provides rudimentary, unofficial "serial over LAN" support. The LOM's field replaceable units (FRU) inventory capability is not used, and motherboard sensor status is unavailable, even in cached form, when the system is powered down.
Deal or no deal?
I came to this review with three questions in mind: Is Nehalem Xserve better than Mac OS X Leopard Server running on Mac Pro? Do existing Xserve owners have a compelling reason to upgrade? And finally, does Nehalem Xserve give users of other brands of rack servers cause to consider a switch?
The first question is one of value. Someone running one to three servers is less likely to be concerned about lights out management, redundant power supplies, the rack form factor, and spare parts kits, key Xserve features with large-scale IT appeal. Next to Nehalem Xserve, Nehalem Mac Pro is the far greener and quieter machine, with more room for storage and a matching hardware RAID option. However, Mac Pro has less RAM capacity, and solid-state storage isn't an option (at least not from Apple). People using Mac Pro as a pedestal server also get the advantage of adding storage with raw SATA drives, an option that Apple precludes on Xserve.
Existing Xserve owners need to upgrade to the Nehalem model, if only because the enormous leap in memory bandwidth makes it possible to do so much more work in the same space. Nehalem and Mac OS X seem positively made for each other; neither is as impressive alone as it is with the other. It's a certainty that Snow Leopard, when it ships this summer, will be at its best on Xserve. Apple built a discrete GPU with dedicated memory into Xserve to take advantage of Snow Leopard's ability to parcel out compute tasks to the 3-D accelerator.
As for whether Nehalem Xserve is strong enough to pull newcomers to the Mac server platform, that's hard to say. It probably should, but Xserve is an odd duck. IT is conditioned to look at x86 rack servers as raw material for handmade solutions. Xserve is a solution in itself, but a review of the hardware fills in only half of the picture. Making an intelligent choice about a Mac server platform requires familiarity with Mac OS X Server, and as Apple kicks off its Worldwide Developer Conference next week, I'll give you a refresh on Mac OS X Server's features, including new capabilities coming to Snow Leopard (10.6). Then you'll have the whole picture.
Apple's Nehalem Xserve packs more into one rack unit than any other server. For one price, you get a best-in-class server and a commercial Unix OS with unlimited client licenses, plus a foolproof management GUI. The 2.26GHz eight-core model outguns and out-greens the original 3GHz, eight-core Harpertown Xserve if you fill it with RAM.