Hi Sahina,
Thanks for your reply.

Let me share my test results with gluster v3 .
I have a 3-node hyperconverged setup with 1 Gbit/s network and SSD (sata-based) for LVM caching.
Testing the bricks  showed higher than the network performance.
1. Tested ovirt 4.2.7/4.2.8 with fuse mounts. Using 'dd if=/dev/zero of=/default/gluster/Mount point/from/ovirt bs=1M count=5000'.
Results: 56MB/s directly on the mount point, 20+-2 MB/s from a VM.
Reads on fuse mount point ->  500+ MB/s
Disabling sharing increased performance from the fuse mount point, nothing beneficial from a VM.

Converting the bricks of a volume to 'tmpfs' does not bring any performance gain for FUSE mount.

2. Tested ovirt 4.2.7/4.2.8 with gfapi - performance in VM -> approx 30 MB/s

3. Gluster native NFS (now deprecated) on ovirt 4.2.7/4.2.8 -> 120MB/s on mount point, 100+ MB/s in VM

My current setup:
Storhaug + ctdb + nfs-ganesha (ovirt 4.2.7/4.2.8)  -> 80+-2 MB/s in the VM. Reads are around the same speed.

Sadly, I didn't have the time to test performance  on gluster v5 (ovirt 4.3.0)  , but I haven't noticed any performance gain for the engine.

My suspicion with FUSE is that when a gluster node is also playing the role of a client -> it still uses network bandwidth to communicate to itself, but I could be wrong.
According to some people on the gluster lists, the FUSE performance is expected ,but my tests with disabled sharing shows better performance.

Most of the time 'gtop' does not show any spikes and iftop shows that network usage is not going over 500 Mbit/s

As I hit some issues with the deployment  on  4.2.7 , I decided to stop my tests for now.

Best Regards,
Strahil Nikolov