Sun Fire X4500 server crams 48 drives into 4U

To anyone with a base level of computer knowledge, the concept of a single system with 48 hard drives seems insane. To IT folks, it's even more outrageous; most disk arrays are limited to 15 drives per shelf and certainly aren't mounted in a server chassis. To Sun, 48 drives in 4U of space is just the newest entry in its line of x64 servers.

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The Sun Fire X4500, nicknamed Thumper, is exactly that: a dual-Opteron server with 48 hot-swappable SATA drives in a single 4U chassis, achieving a raw total of 24TB with 500GB SATA drives. You could fit the entire catalog of the Library of Congress on a single X4500 — 2.5 times over. Armed with four gigabit NICs, 4GB of RAM, and a default installation of Solaris x86, the X4500 is a server in a class all its own.

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Big-box storage

The X4500's internal architecture is as clean as that of any of the other Galaxy servers in Sun's line: 48 top-loading SATA drives cooled by four enormous fans in the front. The server mainboard is a split-level design taking up relatively little space near the rear of the chassis, with two usable PCI-X slots, four gigabit NICs, and Sun's N1 lights-out management processor attached in a special dual-purpose video/management card.

Power is delivered via two huge power supplies situated above the server mainboard. There's a third slot in the rear for another power supply, but the default configuration doesn't require it. I speculate that this bay is reserved to provide additional power should drives even more power-hungry hit the market, or possibly as a space for a local battery to ensure that the X4500 doesn't suffer unnecessarily from an abrupt power outage.

The drives are driven by six SATA controllers, each responsible for eight disks. The first two drives in the chassis are reserved as OS drives, seen as bootable devices in the BIOS, and can be configured in a software mirror. The other 46 drives are up for grabs. Obviously there's no way to get 48 drives into a 4U chassis without top-mounting them, but this configuration makes live drive swaps difficult.

It's also worth noting that simply rack-mounting the 130-pound-plus X4500 required three sizable guys and a lot of sweating. I'm a little worried about the rails shipped with the server — they didn't seem up to the task. In a production environment, I would be sure to place the X4500 at the bottom of a rack or above other well-secured hardware.