[solved] KSM-sharing

[ITN]

Hi folks,

there are 10 more or less identical WIN7-guests on the PROXMOX-server.

but KSM-sharing dont works.

What`s wrong? Any idea?

root@server:~# pveversion -v
proxmox-ve-2.6.32: 3.1-114 (running kernel: 2.6.32-26-pve)
pve-manager: 3.1-24 (running version: 3.1-24/060bd5a6)
pve-kernel-2.6.32-26-pve: 2.6.32-114
lvm2: 2.02.98-pve4
clvm: 2.02.98-pve4
corosync-pve: 1.4.5-1
openais-pve: 1.1.4-3
libqb0: 0.11.1-2
redhat-cluster-pve: 3.2.0-2
resource-agents-pve: 3.9.2-4
fence-agents-pve: 4.0.0-2
pve-cluster: 3.0-8
qemu-server: 3.1-8
pve-firmware: 1.0-23
libpve-common-perl: 3.0-9
libpve-access-control: 3.0-8
libpve-storage-perl: 3.0-18
pve-libspice-server1: 0.12.4-2
vncterm: 1.1-6
vzctl: 4.0-1pve4
vzprocps: 2.0.11-2
vzquota: 3.1-2
pve-qemu-kvm: 1.4-17
ksm-control-daemon: 1.1-1
glusterfs-client: 3.4.1-1

thnx @all

 

[m.ardito]

Re: KSM-sharing

did you try "watch" monitoring described here? https://pve.proxmox.com/wiki/Dynamic_Memory_Management

Marco

 

[ITN]

Re: KSM-sharing

Thank you for reply

root@server:~# watch cat /sys/kernel/mm/ksm/pages_sharing
Every 2.0s: cat /sys/kernel/mm/ksm/pages_sharing Tue Feb 11 14:42:58 2014

0

Thats all. :-(

 

[Patschi]

Re: KSM-sharing

Maybe KSM sharing will only start working when more RAM is in use?

 

[ITN]

Re: KSM-sharing

Just install several KVM virtual machines with the same OS (using at least 50 % of your physical memory on the host) and wait a few minutes.

 

[mo_]

Re: KSM-sharing

like the 50% in the quoted wiki page suggests, theres a threshold that you need to hit before KSM starts doing anything. KSM requires CPU cycles, so theres no point in running KSM if you have a lot of free memory anyhow

 

[m.ardito]

Re: KSM-sharing

I feel like have read somewhere that the 50% threshold is the default, but can be changed... if only I could remember where...

Marco

 

[e100]

Re: KSM-sharing

The 50% threshold is not true from my recollections.

Try these threads:

http://forum.proxmox.com/threads/5041-KSM-with-2-6-35

http://forum.proxmox.com/threads/7530-No-pages_sharing-(KVM-KSM)-after-upgrade-to-1-9

 

[spirit]

Re: KSM-sharing

the defaut threhold is 80% of ram used on host.

(Because ksm use some cpu to scan pages, it's disabled by default and only begin to scan page when host reach 80% of used ram).

This can be tuned in /etc/ksmtuned.conf

 

[dietmar]

Re: KSM-sharing

the defaut threhold is 80% of ram used on host.

(Because ksm use some cpu to scan pages, it's disabled by default and only begin to scan page when host reach 80% of used ram).

This can be tuned in /etc/ksmtuned.conf

To be more elaborate, KSM_THRES_COEF is 20 by default. But this values refers to the amount of 'free' memory, so
KSM is started if (free_memory < (KSM_THRES_COEF*total/100)).

 

[ITN]

Re: KSM-sharing

i have total memory 31,45
20*31,45/100=6,29

KSM started if free_memory<6,29 right?

 

[spirit]

Re: KSM-sharing

i have total memory 31,45
20*31,45/100=6,29

KSM started if free_memory<6,29 right?

Yes

 

[ITN]

Re: KSM-sharing

Ok, thank you all.

Frank

 

[m.ardito]

Re: KSM-sharing

To be more elaborate...

Dietmar I saw you changed the KSM page updating the default threshold to 80%, But at top that page says it's obsolete, in favor of http://pve.proxmox.com/wiki/Dynamic_Memory_Management, which has similar content (but not all), and still says 50%.

It would be better to move all correct content to this last page, and then make a redirect from the first? If you agree, i could make this.

Marco

 

[dietmar]

Re: KSM-sharing

It would be better to move all correct content to this last page, and then make a redirect from the first? If you agree, i could make this.

Ok, I changed the info on that page also. Feel free to add further improvements.

 

[m.ardito]

Re: KSM-sharing

Done, added small info about ksmtuned.conf and some reference links.

Marco