In RHEV 3, Host "Memory Page Sharing" status and KSM status does not match
Environment
- Red Hat Enterprise Virtualization 3.0
- Red Hat Enterprise Virtualization 3.1
Issue
Sometimes Memory Page Sharing Host information shows Inactive but KSM is running. Or Memory Page Sharing Host information shows Active but KSM is not running.
Resolution
It is already fixed in upstream and must be shipped by the next RHEV versions. Memory Page Sharing will always reflect the current KSM status.
Root Cause
KSM is started or stopped according with ksmtuned
policy[1]. On the other hand, the RHEV function checking whether KSM is active or not is called only when a virtual machine is started or stopped. Meanwhile, Administrator Portal can show an outdated information.
A future UI setting for changing this behavior is being tracked in Bugzilla #1026980
[1] - https://access.redhat.com/knowledge/solutions/236253
Diagnostic Steps
Compare the value of Memory Page Sharing in Administration Portal Host General TAB with Host /sys/kernel/mm/ksm/run
file value (0 means KSM Inactive and 1 means KSM active).
This solution is part of Red Hat’s fast-track publication program, providing a huge library of solutions that Red Hat engineers have created while supporting our customers. To give you the knowledge you need the instant it becomes available, these articles may be presented in a raw and unedited form.
Comments