On Fri, Mar 02, 2012 at 02:41:30PM +0200, Harald Hannelius wrote: > >So next is back to the four-node setup you had before. I would expect that > >to perform about the same. > > So would I expect too. But; > > # time dd if=/dev/zero bs=1M count=20000 of=/gluster/testfile > 20000+0 records in > 20000+0 records out > 20971520000 bytes (21 GB) copied, 1058.22 s, 19.8 MB/s > > real 17m38.357s > user 0m0.040s > sys 0m12.501s Right, so we know: - replic of aethra and alcippe is fast - distrib/replic across all four nodes is slow So chopping further, what about: - replic of adraste and helen? This would show whether one of these nodes is at fault. > At least I got double figure readings this time. Sometimes I get > write speeds of 5-6 MB/s. Well, I'm a bit lost when you start talking about VMs. Is this a production environment, and you are doing these dd/cp tests *in addition* to the production load of VM traffic? Or are you doing tests on an unloaded system? Note: mail servers have a nasty habit of doing fsync() all the time, for every single received message. Tools which might be useful to observe the production load: iostat 1 # shows the count of I/O requests and KB read/written per second btrace /dev/sdb | grep ' [DC] ' # shows the actual I/O operations dispatched (D) and completed (C) # to the drive There are also gluster-layer tools but I've not tried them: http://download.gluster.com/pub/gluster/glusterfs/3.2/Documentation/AG/html/chap-Gluster_Administration_Guide-Monitor_Workload.html Regards, Brian.
