On Wed, 2009-04-22 at 20:37 -0300, Flavio Junior wrote: > On Wed, Apr 22, 2009 at 8:11 PM, Andy Wallace <andy@xxxxxxxxxxxxxxxxxxxx> wrote: > > > Although it's not as quick as I'd like, I'm getting about 150MB/s on > > average when reading/writing files in the 100MB - 1GB range. However, if > > I try to write a 10GB file, this goes down to about 50MB/s. That's just > > doing dd to the mounted gfs2 on an individual node. If I do a get from > > an ftp client, I'm seeing half that; cp from an NFS mount is more like > > 1/5. > > > > Have you tried the same thing with another filesystem? Ext3 maybe ? > Are you using RAID right? Did you check about RAID and LVM/partition alignment? > > If you will try ext3, see about -E stride and -E stripe_width values > on mkfs.ext3 manpage. > This calc should helps: http://busybox.net/~aldot/mkfs_stride.html > > Yes, I have (by the way, do you know how long ext3 takes to create a 6TB filesystem???). I've aligned the RAID and LVM stripes using various different values, and found slight improvements in performance as a result. My main problem is that when the file size hits a certain point, performance degrades alarmingly. For example, on NFS moving a 100M file is about 20% slower than direct access, with a 5GB file it's 80% slower (and the direct access itself is 50% slower). As I said before, I'll be working with 20G-170G files, so I really have to find a way around this! -- Andy -- Linux-cluster mailing list Linux-cluster@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/linux-cluster
