Apple RAIDs the enterprise

Not so many years ago, anyone taking Apple seriously in the world of enterprise computing was a subject of mockery. But Apple continues to make headway in its drive to reinvent itself as a serious enterprise computing player. Building on the enthusiastic reception by analysts and users alike of its original Xserve rack-mounted server, the desktop computing pioneer has expanded its high-end offerings to include a clustered server configuration, a 2.5TB 3U RAID array, and a second-generation Xserve that features faster CPUs and enhancements to the cooling systems.

After my look at the new Xserve, and the Xserve RAID, I’m more convinced than ever that Apple’s server hardware stands up with anyone else’s, and not just because its appearance is so striking. Apple has done a very good job of demonstrating how to take what everyone else takes as a commodity — a Unix-like OS — add an interface that even neophytes can cope with, and package it with a solid hardware offering.

The only question a CTO considering Xserve should be asking is: Whether to buy now or wait for a PowerPC G5 variant? Rumors claim “end of this year” is the timeframe for a G5, which might be a stretch, given the challenges involved in keeping two G5 CPUs below melting temperature in a case smaller than 3U. (The G5 case photo that I found on a Google search turned out to be a parody, featuring a Sub-Zero brand freezer.) In the absence of any official road map for the next generation of Xserve, if you’re thinking about buying them now, you probably should, at least until the rumored quad-processor beast ships.

The argument for the current Xserve model is fairly straightforward: it’s a compact 1U package with an OS that’s more manageable out of the box than a Linux system and less expensive than Windows, and it makes even the drabbest server room look cutting-edge. Improvements over the original version include faster G4 processors running at 1.33GHz, enhanced cooling systems that take advantage of the G4’s load-based power consumption, some less-elaborate cooling improvements including more holes in the front of the case, and more efficient hexagonal holes in the rear. A new optical drive features a slot-load mechanism instead of the original Xserve’s tray-load drive. The introduction of Apple’s first serious mass-storage system in the Xserve RAID gives users the ability to address up to 2.5TB of data as a single system that’s easily managed and neatly integrated with the OS.

Radical RAID

The Xserve RAID array uses up to 14 of the same 180GB drive modules that are used in the Xserve itself and contains dual 2-gigabit HSSDC2 (High-Speed Serial Data Connector 2) Fibre Channel controllers, each controller is also equipped with a 10/100 Ethernet interface for management. Each drive has a dedicated ATA/100 drive channel connected to a passive backplane, to wring the most out of the Fibre Channel bandwidth (200MB/sec per controller) while providing optimal failure avoidance. Optional battery backups can provide up to 72 hours of cache data protection in the event of a catastrophic power failure. The dual-port SFP (Small Form-factor Pluggable) Fibre Channel adapter is a separate purchase of $499; though some third-party adapters may become available. The dual RAID controllers support 512MB of cache per controller, though the standard configuration is one-fourth that figure.

In technical specifications, Xserve RAID is state-of-the-art; it can be configured in looped, point-to-point and switched (or fabric) topologies, and supports a variety of basic RAID configurations — RAID 0, RAID 1, RAID 5, and RAID 0+1 — and hybrid RAID options including RAID 10, 30 and 50 — these last involve various software-based methods of mirroring and striping data across multiple hardware-based RAID drive groups. About the only limitation to the amount of data space you can create with multiple arrays is those inherent to the operating system in use. Physically, Xserve RAID is a creampuff to set up: The box racks easily, resting on a support shelf; plug in the cables, and you’re off. For short distances, the Apple adapter comes with copper HSSDC cables that include an SFP transceiver; longer runs of up to a half-kilometer use fiber optic cables with SFP connectors. Serial ports on each power supply allow communication with one or two UPS systems.

Administrators will typically install the RAID Admin management software on the first Xserve in the Fiber Channel network, but this can be set up on other machines as well — Linux, Mac, Solaris, or Windows — for managing multiple Xserve RAID systems. RAID Admin uses Apple’s Zeroconf -based Rendezvous network identification technology for discovery and connection.

The Java-based RAID Admin makes it easy for administrators to configure the array to their needs. Between the hardware indicators on the front and rear of the Xserve RAID’s case and the green-yellow-red markers in RAID Admin, locating a failing or failed component is child’s play. But RAID Admin is good for more than just troubleshooting; it supports advanced features such as LUN (Logical Unit Number) masking, which allows the creation of arrays on a Fibre Channel network that are only visible to certain systems. I was able to create and instantly access a RAID 5 partition that spanned all 14 disks, though as expected, the array did not complete formatting for several hours. Mirroring and striping across arrays is managed with a second utility, the Mac OS X Disk Utility, while any complex Fibre Channel network configurations are identified with the Fiber Channel Info utility. While the three management utilities could be better integrated, the compartmentalization keeps simple configurations simple.

Slotted In

Though the new Xserve — Apple hasn’t seen fit to create any designation more highfalutin’ than “Slot-Load” for the 1.33GHz configuration — is faster than its predecessor, it is somewhat quieter. From a connectivity perspective, the improvements are mixed. The FireWire (IEEE 1394) connection now provides FireWire 800 (Mbps) support on the Xserve’s front ports, and the original FireWire 400 on the rear socket; compared with 400Mbps support on all of the original Xserve’s FireWire interfaces. For anyone who thinks FireWire is strictly for connecting a Sony camera to a Mac, think again. FireWire 800 uses a similar scheme as that found in 2-gigabit Fibre Channel and Gigabit Ethernet to double its speed. It also has a 100m distance limit, making it ideal for applications within a datacenter. But USB compatibility is still limited to version 1.1 of the relevant specification.

Although it’s difficult for 1U servers to scale up, the Xserve scales out nicely and clustered configurations are available from Apple. These generally have more memory than server-based configurations and no optical drive. The G4 CPU’s built-in vector processing capabilities are built around a 128-bit interface, and syncs with the floating-point and integer processors, permitting highly parallel computations. This helps Xserve whip through heavy-duty algorithms, and high-bandwidth applications cough up results quickly.

Xserve RAID, with its relative ease of administration, is a sorely-needed item in Apple’s enterprise computing portfolio. The Xserve itself is already an extraordinary machine that performs yeoman duty as a highly manageable server, and smart CTOs and IT directors should consider it for their use. When Xserve ships with the G5, Apple will have a truly unique offering that IT managers must consider.