[ovirt-users] Super Low VM disk IO via Shared Storage

Dear oVirt, I have executed some tests regarding IO disk speed on the VMs, running on shared storage and local storage in oVirt. Results of the tests on local storage domains: avlocal2: [root@mpollocalcheck22 ~]# dd if=/dev/zero of=/tmp/test2.img bs=512 count=100000 oflag=dsync 100000+0 records in 100000+0 records out 51200000 bytes (51 MB) copied, 45.9756 s, 1.1 MB/s avlocal3: [root@mpollocalcheck3 ~]# dd if=/dev/zero of=/tmp/test2.img bs=512 count=100000 oflag=dsync 100000+0 records in 100000+0 records out 51200000 bytes (51 MB) copied, 43.6179 s, 1.2 MB/s Results of the test on shared storage domain: avshared: [root@mpoludctest4udc-1 ~]# dd if=/dev/zero of=/tmp/test2.img bs=512 count=100000 oflag=dsync 100000+0 records in 100000+0 records out 51200000 bytes (51 MB) copied, 283.499 s, 181 kB/s Why is it so low? Is there anything I can do to tune, configure VDSM or other service to speed this up? Any advice is appreciated. Shared storage is based on Netapp with 20Gbps LACP path from Hypervisor to Netapp volume, and set to MTU 9000. Used protocol is NFS4.0. oVirt is 4.3.4.3 SHE.