Hi All, I have two systems connected via 10GBE . Hardware is new and performs well (more details below). I am hitting problems with write performance. I have spent a few days reviewing previous posts without success. Any advice would be greatly appreciated. Hardware: 4 AMD CPU cores available 6GB RAM allocated LSI raid card (drives in RAID 5, 6 x 10krpm drives) intel 10GBE network cards (currently in cross over between servers with a CAT6A cable) Network performance is reasonable: [ 3] 0.0-10.0 sec 8.21 GBytes 7.05 Gbits/sec MTU is 9000 Direct write to file system is good (a dd twice the size of the ram): dd if=/dev/zero bs=1M of=zero.dat count=12000 12000+0 records in 12000+0 records out 12582912000 bytes (13 GB) copied, 20.673 s, 609 MB/s Write over the gluster mount (I am hoping to achieve around 300MB/sec +): dd if=/dev/zero bs=1M of=zero.dat count=12000 12000+0 records in 12000+0 records out 12582912000 bytes (13 GB) copied, 111.19 s, 113 MB/s The above figure looks just like what I would expect off 1Gbit - however it is definitely at 10GBE link (running around 7gbit/sec) CPU doesn't max out, however it does go higher than I would expect for 111MB/sec. I can see total use go to around 260% (out of 4 cores... so it could go higher to 400%) There is no real disk wait (the raid card has caching and it is enabled) kernel: uname -r 3.2.29 gluster: glusterfs -V glusterfs 3.3.0 built on Jun 6 2012 07:50:10 volume info: gluster volume info Volume Name: vg0lv1 Type: Replicate Volume ID: 0375372e-c8a8-46ce-b152-d7575b0096ab Status: Started Number of Bricks: 1 x 2 = 2 Transport-type: tcp Bricks: Brick1: 10.21.0.1:/mnt/vg1/lv1 Brick2: 10.21.0.2:/mnt/vg1/lv1 Options Reconfigured: performance.cache-size: 1024MB performance.write-behind-window-size: 128MB performance.io-thread-count: 64 performance.flush-behind: on filesystem was created with -I 512 (it is ext4) volfile info: volume remote1 type protocol/client option transport-type tcp option remote-host 10.21.0.1 option remote-port 24007 option remote-subvolume /mnt/vg1/lv1 option transport.socket.nodelay on end-volume volume remote2 type protocol/client option transport-type tcp option remote-host 10.21.0.2 option remote-port 24007 option remote-subvolume /mnt/vg1/lv1 option transport.socket.nodelay on end-volume volume replicate type cluster/replicate subvolumes remote1 remote2 end-volume volume writebehind type performance/write-behind option window-size 128MB option flush-behind on subvolumes replicate end-volume volume iothreads type performance/io-threads option thread-count 32 subvolumes writebehind end-volume