What is the maximum amount of memory and number of CPU cores supported on the HPE Integrity Superdome X with BL920s Gen9 Blades?

Updated -

Issue:

  • The Hewlett Packard Enterprise HPE Integrity Superdome X with BL920s Gen9 Blades system is available from Hewlett Packard Enterprise
    in configurations that may include up to 24TB of memory and 768 logical CPU cores. This maximum configuration is supported by RHEL7 operating system or Red Hat OpenStack Platform.

  • This server may require configuration and tuning options listed below for proper operation.

Environment:

  • RHEL7.2.z Kernel 3.10.0-327.18.2.el7.x86_64 or later
  • Red Hat OpenStack Platform (RHOSP) 8
  • Red Hat OpenStack Platform (RHOSP) 9

Resolution:

  • Systems with a very large configuration that has a high system load will most likely need one or both of the options below to avoid the follow hang:
    "CPU x stuck for 22s" messages to the console.

  • If the hang described above is encountered. First change setting zone_reclaim_mode to 1 and rerun the application(s) to determine the hang no longer occurs.
    echo 1 >/proc/sys/vm/zone_reclaim_mode

  • This will force the system to reclaim pages from memory exhausted numa nodes rather than allocating pages on other nodes. This can result in
    slower startup/initialization times for processes that allocate lots of memory but, faster run times once that are totally up and running.

  • To make this option permanent add this to /etc/sysctl.conf. This option will then be set at boot.
    vm.zone_reclaim_mode = 1

  • To totally eliminate the hang the system administrator can disable Transparent Huge Pages(THP) by:
    "echo never > /sys/kernel/mm/redhat_transparent_hugepage/enabled"

  • This totally eliminates the hang by
    1.) throttling the page allocation so the memory reclaim code can keep up with the demand.
    2.) eliminating the khugepaged splitting up of 2MB pages that happens as part of page reclaim while holding spinlocks.
    Disabling THP does, however, introduce a possiblity of a significant performance reduction for some systems and applications because memory is
    allocated and mapped in only 4KB sections rather than 2MB section.

  • For additional information on disabling redhat_transparent_hugepage please see:
    https://access.redhat.com/solutions/1320153

  • For additional information on setting up kdump on this server please see:
    https://access.redhat.com/solutions/2438911

  • Note: With the HP Integrity Superdome the maximum supported CPUs for RHEL 7.1 is 576 with Haswell-EX cpus. The maximum supported memory for RHEL 7.1 is 24TB.

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