I setup an ext4 repository and OVS3.2.1 access over NFS seemed OK out of the box. The repos having the slowness over NFS were my ZFS repos. I was able to get decent speeds for now by disabling my dedicated ZIL which is OK in my dev environment but I am not sure I will do that in other environments. Our dev NFS system is currently OEL 6 with www.zfsonlinux.com & not sure I am willing to give up the ZFS benefits (ssd cache, compression, dedupe, snapshots, etc) so if I can't figure out a way to make it work natively with proper ZIL on OEL I will likely setup a full Solaris x86 machine and test there. Hopefully the more up-to-date ZFS implemnentation in the most recent Solaris will address the NFS penalty due to OVS oflag=direct type calls over NFS. If I do this I will try to share that info with others as ZFS under OVS is amazing thus far aside from this issue.