Maybe it's cheating by writing sparse files or something of the like because it knows it's all zeros? Create some files locally from /dev/urandom and copy them. I think you'll see much lower performance. Better yet, use bonnie++. Jeff White - Linux/Unix Systems Engineer University of Pittsburgh - CSSD On 03/29/2012 03:34 PM, Jeff Darcy wrote: > On 03/29/2012 03:30 PM, Harry Mangalam wrote: >> I'm doing some perf tests on a small gluster filesystem - 5 bricks on 4 >> servers, all single-homed on the private net. >> >> I've spawned up to 70 simultaneous jobs on our cluster nodes writing files of >> various sizes from /dev/zero to the gluster fs to see what the effect on the >> aggregate bandwith and the data is slightly unbelievable in that it seems to >> exceed the theoretical max of the network. (I used /dev/zero instead of >> /dev/urandom since /dev/urandom couldn't generate data fast enough. >> >> The 35,000 files of the right size do hit the filesystem (of course they're all >> zero's) but the speed at which they transfer exceeds (by quite a bit) the >> theoretical max of a 1 Gb network. >> >> Does gluster (or anything else) do transparent compression? What else would >> explain this oddity? > How do you define "theoretical max of a 1Gb network"? If it's a switched > network, the actual maximum throughput depends on the capabilities of the > switch but is likely to be far in excess of 1Gb/s. Could that be it? Could > you give more detail about the actual traffic patterns and results? > > BTW, this is my favorite message title ever. Thanks for that. :) > > _______________________________________________ > Gluster-users mailing list > Gluster-users at gluster.org > http://gluster.org/cgi-bin/mailman/listinfo/gluster-users
