I stand corrected, it seems that this change is supported. If you go and check the memory optimisation tab you'll find that it is set to "Custom Value" ------------------ Noam Slomianko Red Hat Enterprise Virtualization, SLA team ----- Original Message ----- From: "Noam Slomianko" <nslomian(a)redhat.com&gt; To: mathok1(a)googlemail.com Cc: users(a)ovirt.org Sent: Tuesday, October 16, 2012 5:38:51 PM Subject: Re: [Users] Ovirt Memory Page Sharing or to less memory Short answer: not really Long answer: you can go in to the engine DB -> 'vds_groups' (clusters) table and change the 'max_vds_memory_over_commit' column to what ever value you like. Word of caution: This isn't supported, and i cannot guarantee how will the Ovirt UI or the Host react to this change ------------------ Noam Slomianko Red Hat Enterprise Virtualization, SLA team ----- Original Message ----- From: "Mathok" <mathok1(a)googlemail.com&gt; To: users(a)ovirt.org Sent: Tuesday, October 16, 2012 12:51:05 AM Subject: [Users] Ovirt Memory Page Sharing or to less memory Hello, I have only 3 host with less amount of memory for test purpose and i like to run more vms but i cant start them because they are under the defined memory threshold. It is possible to increase the level of memory page sharing on a cluster above the 200% with a option and start the vms after that change ? or it is possible to deactivate the memory threshold with any option? regards mathok _______________________________________________ Users mailing list Users(a)ovirt.org http://lists.ovirt.org/mailman/listinfo/users _______________________________________________ Users mailing list Users(a)ovirt.org http://lists.ovirt.org/mailman/listinfo/users

2012/10/17 Alan Johnson <alan(a)datdec.com&gt; Same here with ovirt 3.1.0-2 i can't see a change in the UI. But i'm able to start more VMs and hava a higher usag of my swap partiotion so i think the change had the desired effect thank you for your help

On 10/17/2012 11:16 PM, Alan Johnson wrote: that is correct. the default value for "reserved memory" at vm level is based on cluster over commit. cluster over commit can be set to a custom value via the api/sdk/cli. you should validate ksm is up and running. you should also note ksm by default only kicks in around 80% host memory utilization. so if you want to be more aggressive on sharing memory pages (at the expense of a bit more cpu cycles for ksm), you can configure it at vdsm level to start at a lower threshold. also, you should note that during vm startup, until vm goes to up, engine assumes it is taking all of its defined RAM, then moves to check actual ram consumption of the VM. so between ksm configuration, and the time VMs go to up state, you may need to throttle the launch of multiple VMs on same host. CMO - total potential RAM of the VMs on the host should not exceed host ram * CMO. PMG - total reserved RAM of the VMs on the host, should not exceed host ram (that's "close enough to the truth", calculation is taking some overheads into account, etc.)