Well i just tried this ( i never really did read the documents on that part ) and amazingly my loadavg on the kvm host dropped by a factor of 10. All the load was coming out of a heavily loaded VM with pgsql in it that was writing all the time ( zabbix monitoring etc. ). I guess this should really be set as default, not sure if it's up to virt-manager or libvirt.
From: "Jamin W. Collins" <[email protected]> To: [email protected] Sent: Saturday, August 14, 2010 1:16:51 AM Subject: [virt-tools-list] Default use of caching on raw volumes If possible I'd like to get some opinions on the following bug report: https://bugzilla.redhat.com/show_bug.cgi?id=623188 Obviously, I believe that virt-manager should be defaulting to disabling caching for disks backed by raw volumes as qemu suggests. There is a huge performance difference in doing so. AFAIK, there is no difference, in terms of risk, between no cache and Writethrough. I don't quite get Daniel's response and subsequent closing the bug report indicating that it's a policy decision for virt-manager and the like. I filed the report where virt-manager's web site indicated the report should be filed. _______________________________________________ virt-tools-list mailing list [email protected] https://www.redhat.com/mailman/listinfo/virt-tools-list -- Nikolai K. Bochev System Administrator
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