According to IDC, blade servers won't take off until at least next year. But make no mistake--blade servers are the servers of the future. Each blade is a single, 5 ¼-inch-high (3U) self-contained computer--motherboard, processor, memory, disk, and connectivity--that screws into a slot on a standard 19-inch rack. All the blades share a single (or more commonly, dual redundant) power supply, fans, and backbone.
Dell will offer its blade server, dubbed the PowerEdge 1655MC, in two configurations when it ships, expectedly in the third quarter of this year. In a high-density configuration, Dell will pack as many as 504 processors (two per blade) in a single rack.
Dell expects a second configuration, designed for higher performance, to be more popular. Each blade in the high-performance configuration is three times as wide as the high-density blades, so you can pack "only" 84 blades into one rack. That's still six servers in the space where only three could fit previously.
The high-performance system uses a switched Gigabit Ethernet backplane, compared to a 10/100 backplane for the high-density system, and two SCSI drives of any type instead of two ultra-low-profile 40GB IDE drives. Blades in both configurations offer dual redundant connections to the Ethernet backplane. All the hardware is standard, non-proprietary equipment, per Dell's practice, including 1.26GHz Pentium III processors, up to 2GB of SDRAM, and an Ultra320 SCSI controller.
Blade servers have some key advantages over traditional box servers and even over rack-mounted servers. They're compact--you can put more of them in the same space. They use less power than an equivalent number of standalone servers.
Now one announcement of a product that isn't even shipping yet doesn't smack of a trend, nor do HP and Compaq's blade server announcements make this a trend--though Sun and IBM should be next. But if you look at where the industry has been, it becomes clear where it's going.
Blade servers continue an increasing trend toward consolidating computing resources back into the data center. In the pre-PC days, all computing was done in huge air-conditioned computer rooms with impressive picture windows where operators could be seen scurrying from console to console. The PC proliferation shattered the glass houses, and in many organizations, workgroup and departmental servers gained places near the desktops they served.
Recently, however, the need for better system management and curbed costs have pushed computer resources back into a central area. Low-profile rack servers, which stack machines vertically, have become more popular than standalone boxes, because they take up less space and are easy to service. Blades further "stack" servers horizontally, to get the highest server density possible. (At least today--maybe in a few years they'll be stacking them in a third dimension, back to front.)
You probably won't buy your first blade server this year. But if IDC's predictions are on track, you'll want to consider blade servers next year when you add new machines or replace existing ones.