So I've finally completed my first HCI build using the below configuration: 3x Dell PowerEdge R720 2x 2.9 GHz 8 Core E5-2690 256GB RAM 2x250gb SSD Raid 1 (boot/os) 2x2TB SSD jbod passthrough (used for gluster bricks) 1Gbe Nic for management 10Gbe nic for Gluster Using Replica 3 with no arbiter. Installed the latest version of oVirt available at the time 4.2.5. Created recommended volumes (with an additional data volume on second SSD). Not using VDO First thing I did was setup glusterFS network on 10Gbe and set it to be used for glusterFS and migration traffic. I've setup a single test VM using Centos7 minimal on the default "x-large instance" profile. Within this VM if I do very basic write test using something like: dd bs=1M count=256 if=/dev/zero of=test conv=fdatasync I'm seeing quite slow speeds, only 8mb/sec. If I do the same from one of the hosts gluster mounts i.e. host1: /rhev/data-center/mnt/glusterSD/HOST:data I get about 30mb/sec (which still seems fairly low?) Am I testing incorrectly here? Is there anything I should be tuning on the Gluster volumes to increase performance with SSDs? Where can I find out where the bottle neck is here, or is this expected performance of Gluster?