Enabling Memory page sharing to active in RHEV3.0 managing RHEV Hypervisor 6.2
Hi,
I have installed RHEV Hypervisor 6.2 and i am managing it with RHEV manager 3.0. when i checked general tab of the host in RHEV manager, i see memory page sharing is shown as inactive.
can anyone help me to understand why it is inactive??? and how to make it active.
Thanks,
Inbaraj
Responses
It only turns on when the host reaches a certain RAM utilization level, frees up as much memory as is possible, and goes to sleep again. KSM doesn't run constantly
Isn't this service running on your hypervisor by default? I have it running on my hypervisor.
# cat /etc/redhat-release
Red Hat Enterprise Virtualization Hypervisor release 6.3 (20120710.0.el6_3)
# chkconfig ksmtuned --list
ksmtuned 0:off 1:off 2:off 3:on 4:on 5:on 6:off
# service ksmtuned status
ksmtuned (pid 9004) is running...
KSM and tuning with KVM or RHEV I think can be confusing at times as you can use either the RHEV Hypervisor or configure RHEL as a Hypervisor (as I am sure most people realize). Also - I believe the attention and interaction with KSM is more evident now, whereas it was more "behind the scenes" previously.
The RH318 course reviews this topic and has the following to say about it (paraphrasing, of course ;-)
* This feature is enabled by default by RHEV-M on the RHEV-H hosts and managed Red Hat Enterprise Linux 6 hypervisors
* is controlled by ksmtune
* is dynamically disabled/enabled as "memory presure rises"
You can enable KSM on a RHEL 6 host. It is installed by the qemu-kvm package.
RHEV 3.1 (beta) now offers 3 different "modes" under Memory Optimization for the Cluster Config
(pg 30 - Red Hat Enterprise Virtualization 3.1 Beta Administration Guide)
None (disables memory sharing)
Optimized for Server Load (Sets the memory page sharing threshold to 150% of the system memory on each host.)
Optimized for Desktop Load (Sets the memory page sharing threshold to 200% of the system memory on each host.)
I will be building a KVM (non-managed) host later today for a Lab project and I will review whether ksmtuned is running all of the time.
I will be referncing the following page to ensure I understand what I am reviewing:
Welcome! Check out the Getting Started with Red Hat page for quick tours and guides for common tasks.
