How to check if system RAM is faulty in Red Hat Enterprise Linux?

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  • Red Hat Enterprise Linux


  • How to check if system memory (RAM) is faulty in Red Hat Enterprise Linux?


  • Red Hat Enterprise Linux ships a memory test tool called memtest86+. It is a bootable utility that tests physical memory by writing various patterns to it and reading them back. Since memtest86+ runs directly off the hardware it does not require any operating system support for execution.

  • This tool is available as an RPM package from Red Hat Network (RHN) as well as a boot option from the Red Hat Enterprise Linux rescue disk.

  • To boot memtest86+ from the rescue disk, you will need to boot your system from CD 1 of the Red Hat Enterprise Linux installation media, and type the following at the boot prompt (before the Linux kernel is started):

boot: memtest86
  • If you would rather install memtest86+ on the system, here is an example of how to do it on a Red Hat Enterprise Linux 5 machine registered to RHN:
# yum install memtest86+
  • For the Red Hat Enterprise Linux version 4, perform the following command to install memtest86+. Make sure current system has been registered to RHN:
# up2date -i memtest86+
  • Then you will have to configure it to run on next reboot:
# memtest-setup 
  • After reboot, the GRUB menu will list memtest. Select this item and it will start testing the memory.

    • Please note that once memtest86+ is running it will never stop unless you interrupt it by pressing the Esc key. It is usually a good idea to let it run for a few hours so it has time to test each block of memory several times.
  • memtest86+ may not always find all memory problems. It is possible that the system memory can have a fault that memtest86+ does not detect.

Root Cause

  • A common cause for needing to run memtest86+ is when the system becomes sluggish, unresponsive or panics repeatedly, and the logs show "Machine Check Exception.

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