Dueling blades

IT HAS BEEN a long, strange trip for RLX Technologies. A blade server pioneer, RLX has gone from promising start-up to controversial innovator (it was the poster child for Transmeta's Crusoe chip in the server space) to pragmatic good citizen, content to toe the Intel party line. Along the way, the market it helped establish -- high density, low-voltage server devices for Web applications -- became decidedly more crowded thanks to a surge of interest from various industry heavy hitters.

When it comes to Intel-based enterprise server platforms, nobody hits more heavily than Compaq. Just when it looked like the whole blade server experiment was running out of steam, Compaq unveiled its remarkably RLX-like Proliant BL10e.

Compaq's entry had two effects: It legitimized the underlying technical premise that high-density plus low power consumption is a good thing; and it forced RLX to seriously reconsider its Transmeta-only stance. RLX responded by fielding a compelling new Intel-based platform -- the System 300ex -- and was first to market with an 800MHz Server Blade solution. (At press time, Compaq was offering only a 700MHz part.)

The race was on! Would the title go to the swift RLX, or would the experience and sheer technical might of the Compaq juggernaut drown the pioneering upstart in a sea of product family synergy and brand loyalty?

Getting down to business

We really wanted to construct an "apples to apples" comparison, but Compaq's inability to provide us with an 800MHz part by press time left us with no choice but to use its slower 700MHz Pentium III-based blade. The megahertz deficit showed: During testing with CSA Research's ASP Stress 3.0, which simulates a Microsoft ASP-based, three-tier Web application, the Compaq BL10e system took as much as 30 percent longer to complete the same SQL Server transaction loop, depending on client workload.

We faced some challenges in designing a benchmark test for this review. Blade servers are, by their very nature, self-contained computing "appliances." As such, they place a number of restrictions on application design, including the need to accommodate load balancing. Many Web applications require modification before they can run seamlessly across a cluster of identical servers.

In our case, we needed to modify how we handled session identification, because the different instances of the IIS (Internet Information Server) often generated identical session IDs on both blades. It's this kind of hidden gotcha that can derail the otherwise seamless "scale-out" -- scaling horizontally with more devices, as opposed to vertically via bigger and/or faster CPUs -- message that has become the mantra du jour of the server blade community.

The aforementioned performance delta notwithstanding, the Compaq and RLX solutions are functionally quite similar. Both provide excellent blade density: 24 per 3U rack with RLX System 300ex and 20 per 3U rack with Compaq ProLiant BL10e. Both also provide cable aggregation options for the back of the chassis; RLX provides a high-density RJ21 connection whereas Compaq offers a choice of RJ21, RJ45 or an integrated four-port, gigabit-switched backbone.