Yes, jumbo frames were enabled and the following networking tuning was applied ;-)

net.ipv4.tcp_wmem = 4096 65536 16777216
net.ipv4.tcp_rmem = 4096 87380 16777216
net.core.wmem_max = 16777216
net.core.rmem_max = 16777216
net.core.wmem_default = 65536
net.core.rmem_default = 87380
net.core.netdev_max_backlog = 30000

- Chris
________________________________________
From: Adrian Sevcenco [[log in to unmask]]
Sent: Wednesday, July 03, 2013 2:10 PM
To: [log in to unmask]
Cc: Brown, Chris (GE Healthcare)
Subject: Re: KVM + NFS Performance (ZFS/BTRFS/EXT4)

On 07/03/2013 09:23 PM, Brown, Chris (GE Healthcare) wrote:
> -- Test Config #8 --
> Max Read: 652.4
> Max Write: 670.4
are you sure you used 9k frames in your network configuration?
I am very interested in your results and work (many thanks btw for
sharing) and i heard about better results with jumbo frames..

Thanks!
Adrian