Re: [ovirt-users] strange iscsi issue
Hi,
Thank you for your reply.
I'm sorry but I don't think so. This storage is fast, because it is a SSD based
storage, and I can read/write to it with fast performance.
I know, in virtual environment the I/O always slowest than on physical, but here I have a
very large difference.
Also, I use ext4 FS.
Thanks
Tibor
----- 2015. szept.. 8., 0:40, Alex McWhirter alexmcwhirter(a)triadic.us írta:
Unless you're using a caching filesystem like zfs, then
you're going to be
limited by how fast your storage back end can actually right to disk. Unless
you have a quite large storage back end, 10gbe is probably faster than your
disks can read and write.
On Sep 7, 2015 4:26 PM, Demeter Tibor <tdemeter(a)itsmart.hu> wrote:
>
> Hi All,
>
> I have to create a test environment for testing purposes, because we need to
> testing our new 10gbe infrastructure.
> One server that have a 10gbe nic - this is the vdsm host and ovirt portal.
> One server that have a 10gbe nic - this is the storage.
>
> Its connected to each other throught a dlink 10gbe switch.
>
> Everything good and nice, the server can connect to storage, I can make and run
> VMs, but the storage performance from inside VM seems to be 1Gb/sec only.
> I did try the iperf command for testing connections beetwen servers, and it was
> 9.40 GB/sec. I have try to use hdparm -tT /dev/mapper/iscsidevice and also it
> was 400-450 MB/sec. I've got same result on storage server.
>
> So:
>
> - hdparm test on local storage ~ 400 mb/sec
> - hdparm test on ovirt node server through attached iscsi device ~ 400 Mb/sec
> - hdparm test from inside vm on local virtual disk - 93-102 Mb /sec
>
> The question is : Why?
>
> ps. I Have only one ovirtmgmt device, so there are no other networks. The router
> is only 1gbe/sec, but i've tested and the traffic does not going through this.
>
> Thanks in advance,
>
> Regards,
> Tibor