HP bests Sun in a dual-core server duel

Hewlett-Packard's four-processor server is physically larger than the Sun server: It's 7 inches high (4U), which means you can pack 10 of them in a standard 42U rack. Internal storage is limited to four Ultra320 SCSI drive bays, plus one optical/floppy bay that can be converted to a hard-drive bay. The server sports an integrated dual-channel RAID 5 controller that's for use only with the internal drives.

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Beyond the limited storage, the server has eight PCI-X slots -- two 64-bit 133MHz, the others 64-bit 100MHz, all full-length. Unfortunately, none is hot-swappable, and despite the fact that this server's CPUs have the bandwidth to drive PCI-Express cards, the backplane doesn't support that faster I/O standard.

Internally, the DL585 is designed around an active main logic board, which supports four plug-in modules, each of which contains one Opteron processor and four memory slots. (The design of the processor's integrated memory controller requires that each processor has its hardwired memory, but one processor can access another processor's RAM across the HyperTransport bus.) The server design requires that either two or four identical processor modules be installed. The upgrade from single-core to dual-core functionality is achieved simply by swapping these modules -- a simple operation. Performing a processor replacement or upgrade on the Sun Fire V40z is more complicated.

Although both servers offer dual hot-swap power supplies, HP's are accessible from the front, making servicing easier in those rare cases when the power must be changed. What truly makes a difference in serviceability is a little panel inside the server (under the top cover) filled with dozens of LEDs. These illuminate to help identify a faulty part. Many other parts, such as the myriad hot-swap fans, also have LEDs that light up when something goes wrong.

Organizations thinking about high-availability operations might tilt in favor of the ProLiant DL585 over the Sun Fire V40z due to the more accessible power supplies and easier-to-troubleshoot, better way of swapping out a single processor. The Web-based Integrated Lights Out management processor is also far easier to use than the SSH-based processor in the V40z. Beyond that, there's no reason to believe that the components in the HP box are more reliable -- it's just that the box is easier to service. Of course, neither of these systems is a true high-availability server; both lack RAID memory, for example, and processor fail-over. They're just a couple of steps above entry-level, in that regard.

Sun Fire V40z

As is the ProLiant DL585, the Sun Fire V40z is a four-processor server that originally shipped with single-core chips but has since been upgraded to support the dual-core chips. I worked with a 2.2GHz version. At 5.25 inches high (3U), the Sun server is slightly smaller than the HP DL585, allowing you to fit 14 of them, as opposed to 10, into a standard rack. That gives a significant process-density benefit for clusters or datacenters: A fully laden rack of DL585 servers has 40 Opteron processors, while the V40z has 56.

There are very few trade-offs that can be associated with the smaller space. The V40z has seven PCI-X slots, rather than eight, although some are half-size. None is hot-swappable, and there's no option for PCI-Express.