[Gluster-users] Basic gluster questions

[John Hanks]

Hi,

I'm setting up gluster for the first time and have a single server
with two bricks set up for testing:

[root at filer-jdn1bp1 etc]# gluster volume info

Volume Name: projects
Type: Distribute
Status: Started
Number of Bricks: 2
Transport-type: tcp
Bricks:
Brick1: filer-jdn1bp1:/glusterfs/0.0
Brick2: filer-jdn1bp1:/glusterfs/0.1
Options Reconfigured:
nfs.disable: on

Mounting this volume on the server or on a separate client over a 10
Gbps link is working, but I'm seeing weird performance patterns. If I
do this:

time sh -c "dd if=/dev/zero of=./testfile count=32768 bs=1M; sync"

in the glusterfs mounted directory on either client I see rates of
~250 MB/s but if I try to copy files onto the volume with either rsync
or cpio pass-thru, the rates drop to < 10 MB/s. The directories I am
attempting to copy are mostly large files (> 10 GB) and as I watch
cpu, network and disk i/o stats, nothing seems to be stressed or
blocked, it's just slow.

I've been searching for documentation on how to possibly tune this or
track down the bottleneck but not having much luck. Most things that
turn up in searches seem to apply to older gluster versions and the
3.2 documentation is pretty sparse with respect to tuning things.

Any suggestions for what I am doing wrong with this setup or any
pointers to documentation on how to troubleshoot/tune this would be
appreciated, especially any "intro for dummies" type docs that could
fill in the big gaps in my understanding of how gluster works. I'm
open to an RTFM reply, just haven't found the right manual yet myself
and would appreciate a pointer :)

Thanks,

jbh