What are the supported limits for CPU and RAM on the Fujitsu PRIMEQUEST 1800 running Red Hat Enterprise Linux 5?

Updated -

Issue

  • At the time Fujitsu submitted its certification request for the PRIMEQUEST 1800, the Red Hat Enterprise Linux 5 (RHEL 5) supported limits for x86_64-based systems were 64 logical processors (including hyper-threading) and 256GB of memory, as stated here: http://www.redhat.com/rhel/compare/. As the PRIMEQUEST system can be configured with memory and processor amounts in excess of the supported RHEL 5 limits, it was subjected to extended testing beyond the normal hardware certification tests in order to achieve certification with configurations that exceed the supported CPU and memory amounts for RHEL 5.

Environment

  • Fujitsu PRIMEQUEST 1800 system with eight eight-core Intel® Xeon® 7500-series processors (codenamed "Nehalem EX") in configurations up to 128 logical processors and up to 1TB of memory.
  • Fujitsu PRIMEQUEST 1800 system with six ten-core Intel® Xeon® 8800-series processors (codenamed "Westmere EX") in configurations up to 120 logical processors and up to 1TB of memory.
  • Fujitsu PRIMEQUEST 1800 system with eight ten-core Intel® Xeon® 8800-series processors (codenamed "Westmere EX") in configurations up to 80 logical processors (hyperthreading disabled) and up to 1TB of memory.

Resolution

  • The PRIMEQUEST 1800 is certified on RHEL 5.4.z errata kernel https://rhn.redhat.com/errata/RHSA-2009-1670.html to support up to 128 logical CPUs when using Intel® Xeon® 7500-series processors and up to 512GB of memory.
  • The PRIMEQUEST 1800 is certified on RHEL 5.5 to support up to 128 logical CPUs when using Intel® Xeon® 7500-series CPUs and up to 1TB of memory.
  • The PRIMEQUEST 1800 is certified on RHEL 5.5 to support up to 120 logical CPUs when using Intel® Xeon® 8800-series processors with hyperthreading enabled and up to 1TB of memory. In this configuration, the system would have six of the eight processor sockets populated.

  • The PRIMEQUEST 1800 is certified on RHEL 5.5 to support up to 80 logical CPUs when using Intel® Xeon® 8800-series processors with hyperthreading disabled and up to 1TB of memory.

Note, RHEL 5.5 or newer may be required to fix specific problems such as Bugzilla ticket 507333 (Support Intel multi-APIC-cluster systems) whereby the TSC (Time Stamp Counter) can be out of sync between processors in versions of RHEL prior to RHEL 5.5. For any system running RHEL 5.4.z or 5.5, you must also update /etc/sysctl.conf to include the statement "kernel.softlockup_thresh=60" without the quotes.

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