On Thu, 2014-01-09 at 09:53 +0100, Sander Grendelman wrote: > On Thu, Jan 9, 2014 at 9:39 AM, Markus Stockhausen > <stockhau...@collogia.de> wrote: > >> Von: squadra [squa...@gmail.com] > >> Gesendet: Donnerstag, 9. Januar 2014 09:30 > >> An: Markus Stockhausen > >> Cc: Karli Sjöberg; users@ovirt.org > >> Betreff: Re: [Users] Experience with low cost NFS-Storage as VM-Storage? > >> > >> try it, i bet that you will get better latency results with proper > >> configured iscsitarget/initiator. > > > > I guess you did not take time to read the hole post. The latency I speak > > of comes ontop the NFS latency. So my setup has > > > > - 83us latency per I/O in the hypervisor on a NFS share > > - 450us latency per I/O in the VM on a disk hosted on the same NFS share > > > > If ISCSI could reduce latency to 40us instead of 83us in our wishfulst > > dreams > > the QEMU penalty hits too hard. > > There are some interesting tests here: > http://www.linux-kvm.org/page/Virtio/Block/Latency
Very interesting: "...23% overhead compared to a host read request. This deserves closer study so that the overhead can be reduced." Good to know people know and are at least thinking about it:) Seeing as it´s such a fast-paced development, have you done any benchmarks on different distributions as well? I mean like comparing the same test against both, say Fedora and CentOS, to see if that makes any difference? /K > Results seem to depend a lot on the guest OS IO stack/drivers (I see > you use win2k3?). > _______________________________________________ > Users mailing list > Users@ovirt.org > http://lists.ovirt.org/mailman/listinfo/users _______________________________________________ Users mailing list Users@ovirt.org http://lists.ovirt.org/mailman/listinfo/users
