[solved] KSM-sharing

I

ITN

Member
Aug 24, 2009
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Hi folks,

there are 10 more or less identical WIN7-guests on the PROXMOX-server.
guests.jpg
but KSM-sharing dont works.
ksm.jpg
What`s wrong? Any idea?
Code: 
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
 
Last edited:
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. :-(
 
Re: KSM-sharing

ksm2.jpg
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.
Click to expand...
 
Last edited:
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
 
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
 
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
 
Re: KSM-sharing

spirit said:
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
Click to expand...

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)).
 
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Reactions: giovannik
Re: KSM-sharing

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

KSM started if free_memory<6,29 right?
 
Re: KSM-sharing

dietmar said:
To be more elaborate...
Click to expand...

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
 
Re: KSM-sharing

m.ardito said:
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.
Click to expand...

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