I've been having one heck of a time for nearly the entire time I've been running ovirt with disk IO performance.  I've tried a variety of things, I've posted to this list for help several times, and it sounds like in most cases the problems are due to design decisions and such.

My cluster has been devolving into nearly unusable performance, and I believe its mostly disk IO related.  I'm currently using FreeNAS as my primary VM storage (via NFS), but now it too is performing slowly (it started out reasonable, but slowly devolved for unknown reasons).  

I'm ready to switch back to gluster if I can get specific recommendations as to what I need to do to make it work.  I feel like I've been trying random things, and sinking money into this to try and make it work, but nothing has really fixed the problem.

I have 3 Dell R610 servers with 750GB SSDs as their primary drive.  I had used some Seagate SSHDs, but the internal Dell DRAC raid controller (which had been configured to pass them through as a single disk volume, but still wasn't really JBOD), but it started silently failing them, and causing major issues for gluster.  I think the DRAC just doesn't like those HDDs.

I can put some real spinning disks in; perhaps a RAID-1 pair of 2TB?  These servers only take 2.5" hdd's, so that greatly limits my options.

I'm sure others out there are using Dell R610 servers...what do  you use for storage?  How does it perform?  What do I need to do to get this cluster actually usable again?  Are PERC-6i storage controllers usable?  I'm not even sure where to go troubleshooting now...everything is so sloooowwwww.  

BTW: I had a small data volume on the SSDs, and the gluster performance on those was pretty poor.  performance of the hosted engine is pretty poor still, and it is still on the SSDs.