Hello! 2008/12/12 Matt Lawrence <matt.lawrence at tamu.edu>: > I am seeing extremely slow performance with glusterfs. [...] > Writing directly to the underlying filesystem: > > -bash-3.2# dd if=/dev/zero of=/glusterfs/shelf-1/testing count=20M [...] > 10737418240 bytes (11 GB) copied, 230.862 seconds, 46.5 MB/s > > > Writing through glusterfs with no readahead/writebehind: > > -bash-3.2# dd if=/dev/zero of=/storage/testing count=20M [...] > 10737418240 bytes (11 GB) copied, 3429.89 seconds, 3.1 MB/s > > > Using the above configuration is even slower: > > -bash-3.2# dd if=/dev/zero of=/storage/testing count=20M [...] > 10737418240 bytes (11 GB) copied, 4379.16 seconds, 2.5 MB/s > > > What should I be trying to improve performance? I really need help! IIRC: - GlusterFS 1.3.x has problems with communication overhead. As a result, transporting small blocks of data is very slow. - (11GB data /20M blocks ~0,5k blocksize) looks small to me I'd try a bigger blocksize with dd to check if that really is the problem. (e.g. -bs=64k or even -bs=1M) If that helps, I'd try writebehind on the client to let GlusterFS transport bigger blocks. http://www.gluster.org/docs/index.php/GlusterFS_Translators_v1.3#Write_Behind_Translator Harald St?rzebecher
