Red Hat releases big-iron update

Red Hat released an update to its premium Linux product that supports 64-processor x86 servers, and even larger configurations of machines using IBM Power and Intel Itanium chips are coming.

Red Hat Enterprise Linux is the leading commercial version of the open-source operating system. Red Hat released Update 3 on Tuesday, taking Linux to multiprocessor heights previously reserved for the Unix operating system after which Linux is modeled.

New processor technology coming to market means that supporting 64 processors no longer necessarily means a customer has a multimillion-dollar refrigerator-size server. One change is the arrival of multicore chips, which have multiple processing engines on a single slice of silicon. Another change is multithreading, in which a single processor core can run more than one instruction sequence at the same time.

Red Hat's multiprocessor support is for "logical" processors; a server with 64 logical processors could have 64 single-core processors; 16 dual-core, dual-thread Xeon processors as in the IBM x460 server; or 16 quad-core processors when those models become available in 2007.

RHEL already supported 64-processor Itanium servers. The update extends that level of support to machines with IBM's Power processor. In addition, Update 3 includes a "technology preview" of support for as many as 256 Itanium processors and 128 Power processors.

Another change with the new version is support for Intel's "Montecito" processor, the first dual-core Itanium model. It's expected to ship from Intel in the second quarter and arrive in Hewlett-Packard servers in the third quarter.

Red Hat added a technology preview version of the OpenIB InfiniBand software, which today is used chiefly to link many machines into a high-performance technical computing cluster.

[Marcus Westrup]

How well does it scale?

Last I heard, Linux kernel performance falls off sharply with more than 16 logical processors. Has Red Hat found a way around this, or is this update just market-speak?