On Thu, 2014-01-09 at 09:53 +0100, Sander Grendelman wrote:
On Thu, Jan 9, 2014 at 9:39 AM, Markus Stockhausen <stockhausen@collogia.de> wrote:
Von: squadra [squadra@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