Hi Everyone, Hope your day has been going well. I tried emailing this in a week or so ago, but i do not think that it got emailed to the group. I am just trying again, but apologies in advanced if you have already read this. I am currently using GlusterFS as a distributed SAN backend for the Xen based cloud platform we are developing. We deploy Xen virtuals on pairs of servers using GlusterFs V3 in replicate mode on Debian Stable (Lenny) with Xen 3.2.1 as the hypervisor. I am currently experiencing a weird issue where within the virtual machines (DomU) running on a GlusterFS mount only receive around 10-18MB/s write speeds, but full speed reads. Our hardware for each node is Dual Core Xeon Processors, 8GB of RAM and 4 * High Speed SATA drives (RAID 10, around 160MB/s writes and reads). If I write a file to the Gluster mount in the Dom0 (host) we receive around 90-100MB/s writes (maxing out the GigE link). If I run the virtual machine on the disks without Gluster I get much higher speeds within the DomU of around 80-90MB/s. This slow down only appears to occur on writes. Does anyone with a better understanding of GlusterFS, Fuse and filesystems have an idea why this is slowing down. The underlying file system is Ext3 using TAP:AIO within Xen to connect to a file image based disk. This is without using gluster fuse client (what benefits does this give?) and Gluster version 3.0.4. Many Thanks Sheng Here is the current configuration of the servers in replicate: Server: volume posix type storage/posix option directory /export end-volume volume locks type features/locks subvolumes posix end-volume volume brick type performance/io-threads option thread-count 8 subvolumes locks end-volume volume server type protocol/server option transport-type tcp option auth.addr.brick.allow 10.*.*.* subvolumes brick end-volume Client: volume remote1 type protocol/client option transport-type tcp option remote-host node01 option remote-subvolume brick end-volume volume remote2 type protocol/client option transport-type tcp option remote-host node02 option remote-subvolume brick end-volume volume replicate1 type cluster/replicate subvolumes remote1 remote2 end-volume volume writebehind type performance/write-behind option window-size 1MB subvolumes replicate1 end-volume volume cache type performance/io-cache option cache-size 512MB subvolumes writebehind end-volume
