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.

The Bottom Line Sun Fire X4500 Server Sun Microsystems, sun.com Excellent  8.8 criteria score weight Configuration 8 20% Management 9 20% Performance 9 20% Scalability 9 20% Security 9 10% Value 9 10% Cost: As tested with 24TB raw storage, $51,995 Platforms: Solaris, Red Hat Linux, Windows Bottom Line: The X4500 is nicknamed the Thumper for a reason – 48 SATA drives in a single 4U chassis accompanying a dual-Opteron server with two PCI-X slots. There’s no hardware RAID, however, and running anything but Solaris with ZFS is going to artificially hamstring the box. It’s not going to supplant the SAN anytime soon, but the X4500 will certainly make waves. About our Reviews and Scoring Methodology

[ See also: InfoWorld Technology of the Year Awards Hardware winners | Screencast: Sun's ZFS on Thumper ]

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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But what's it really for? Based on the performance levels I saw during my review, I'd say anything that requires lots of fast storage.

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.

What is it good for?
Sun is marketing the X4500 as an enormous storage repository for applications with enormous storage needs (such as IP surveillance) and as a single-point storage server for apps running on other servers. Unlike most storage devices, however, the server runs a standard build of Solaris, Red Hat Enterprise Linux, or Windows, and each drive is independent, without any hardware RAID.

For Linux and Windows, this is a problem, as the default file systems on those OSes aren't really equipped to deal with this number of drives in a single system, nor with the file system sizes you can achieve with the X4500. Those operating systems can make use of the X4500, but with limited I/O speeds, higher CPU utilization, and the requirement that the 48 drives be cut into smaller logical segments. For instance, the default file system on RHEL4, ext3, is limited to 8TB, and it's not possible to create a software RAID with more than 20 devices.

By leveraging Sun's ZFS (Zettabyte File System) under Solaris, however, the playing field changes drastically. ZFS can address all the disks in a single logical array, and can easily handle a 24TB file system -- and even a 48TB file system when X4500 is certified to run with 1TB SATA drives. (Check out our analysis of ZFS and our screencast demo for more on this file system.)