Are you duplicating the traffic over the same physical network by relaying through the VM, rather than writing directly to network storage, thereby halving the write performance?

Assuming you're on a GigE network, are all the network devices running in full duplex?

Just some guesses based on the fact that the throughput is almost exactly half.

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On Thu, Sep 26, 2013 at 5:23 AM, Stefano Stagnaro <> wrote:

I'm testing oVirt 3.3 with GlusterFS libgfapi back-end. I'm using a node for engine and one for VDSM. From the VMs I'm mounting a second GlusterFS volume on a third storage server.

I'm experiencing very bad transfer rates (38MB/s) writing from a client to a VM on the mounted GlusterFS. On the other hand, from the VM itself I can move a big file from the root vda (libgfapi) to the mounted GlusterFS at 70MB/s.

I can't really figure out where the bottleneck could be. I'm using only the default ovirtmgmt network.

Thank you for your help, any hint will be appreciated.

Stefano Stagnaro
IT Manager

Prisma Engineering S.r.l.
Via Petrocchi, 4
20127 Milano Italy

Tel. 02 26113507 int 339
skype: stefano.stagnaro

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