IBM and HP spar over blade server superiority

HP says that its blade servers run cooler than IBM's. IBM tests show that HP blades can burn through memory. And users say both vendors' blades can overheat in dense data centers.

Earlier this year, when Hewlett-Packard Co. took pains to prove that its blade servers were cooler and more power...

efficient than IBM's, IBM volleyed back with results indicating that its blades run cooler and that HP blades run hot enough to burn memory. With all this vendor mudslinging over reliability and performance, who is telling the truth? was unable to locate HP blade users for this article with complaints about the overheating that creates memory depletion. But despite claims to the contrary, some users have reported heat issues in their data centers. Now, on the heels of a recent IBM study comparing IBM and HP blade servers, questions remain about whether these tests are useful and how users can judge which blade server is most appropriate for their data center environment.

Results may beg questions, not answers
Joe Clabby, an analyst at Yarmouth, Maine-based Clabby Analytics, agreed to sponsor IBM research comparing its blade servers with those of HP. This summer, Clabby visited an IBM BladeCenter benchmarking and testing laboratory in Raleigh, N.C., to oversee tests comparing the IBM BladeCenter H with the HP BladeSystem c-Class architecture and evaluate the results.

 Let any blade get too hot, and the components will become less reliable and prone to failure.
Martin MacLeod,
blade server consultantBlade Watch

In conducting this isolated test, of course, IBM had an ulterior motive: that is, to demonstrate that under certain stress workloads, HP's blade memory modules run 10 degrees to 15 degrees hotter than the uppermost range typically recommended by most memory manufacturers, which is 90 degrees Fahrenheit. A similar test is also broadcast via YouTube by IBM's thermal engineer Vinod Kamath.

Nevertheless, Clabby concurred with IBM's analysis. "HP blades run hotter than IBM BladeCenter under the same workload," Clabby reported. "What this means is that, in heavy workload environments, HP may be 'cooking' its memory modules [by] running memory out of spec for extended periods of time. ... This kind of situation can lead to some serious reliability/availability problems."

In the test, HP equipment included 15 BL460x blades running dual 2.33 GHz Intel Xeon 5345 CPUs, with eight 2 GB dual in-line memory modules (DIMMS), one 73 GB 10k rpm disk drive, all in an HP c7000 enclosure with six power supplies and 10 fans.

IBM's BladeCenter H included 14 HS21xm servers with the same Intel Xeon processors, 8X2GB DIMMs, four power supplies and two blowers.

The test took place in a 77-degree room containing two pieces of test equipment: an Agilent Data Acquisition Switch Unit to measure voltage output, and an HP Testmobile Data Acquisition Module to measure temperature.

In that same test environment, the IBM memory modules never exceeded the 85-degree mark, which is the high-end temperature range recommended by most manufacturers. The temp ran closer to 80 degrees throughout the entire test, Clabby reported.

IBM's test followed tests publicized by HP in March that show HP BladeSystem c-Class uses up to 27% less power than the IBM BladeCenter-H in similar configurations in "real world" blade server environments. The

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