Re: [Users] Experience with low cost NFS-Storage as VM-Storage?
On Thu, Jan 9, 2014 at 9:39 AM, Markus Stockhausen
<stockhausen(a)collogia.de> wrote:
> Von: squadra [squadra(a)gmail.com]
> Gesendet: Donnerstag, 9. Januar 2014 09:30
> An: Markus Stockhausen
> Cc: Karli Sjöberg; users(a)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
Results seem to depend a lot on the guest OS IO stack/drivers (I see
you use win2k3?).