> --------- > > Write test 2, VM (Debian 6, VirtIO, stored as qcow2 on /vm_storage): > > /dev/vda2 on / type ext4 (rw,errors=remount-ro) > > echo 3 > /proc/sys/vm/drop_caches > time dd if=/dev/zero of=./bigfile bs=1M count=5000 > > Result: > > 5000+0 records in > 5000+0 records out > 5242880000 bytes (5.2 GB) copied, 796.309 s, 6.6 MB/s > > real 13m16.626s > user 0m0.000s > sys 0m3.700s > > -------- Not that this helps, just duplicated your test on my test setup as a reference point. Your performance does seem a little worse than expected. [root at glustertestc1 v1]# time dd if=/dev/zero of=./bigfile bs=1M count=5000 5000+0 records in 5000+0 records out 5242880000 bytes (5.2 GB) copied, 173.744 s, 30.2 MB/s real 2m53.800s user 0m0.022s sys 0m8.496s This is with servers (replicated gluster volume spread over 2 servers), and the physical disks are on a gigabit ethernet iSCSI SAN with 10K drive, so not exactly high speed. I find with my testing performance for large files is tolerable, but writing of many small files is terrible with gluster. For reference, here was timing of virtual gluster server: [root at glustertests1 data1]# time dd if=/dev/zero of=./bigfile2 bs=1M count=5000 5000+0 records in 5000+0 records out 5242880000 bytes (5.2 GB) copied, 87.2035 s, 60.1 MB/s real 1m27.237s user 0m0.006s sys 0m5.872s (My test clients and servers are all ESXi 4.1 VMs running Scientific Linux 6.1). How is your network latency between servers and clients? [root at glustertestc1 v1]# ping 10.0.12.141 -c 1000 -q -A -s 8000 PING 10.0.12.141 (10.0.12.141) 8000(8028) bytes of data. --- 10.0.12.141 ping statistics --- 1000 packets transmitted, 1000 received, 0% packet loss, time 163ms rtt min/avg/max/mdev = 0.114/0.132/1.638/0.061 ms, ipg/ewma 0.163/0.124 ms (My test clients and servers are all on the same physical box. Guess it might be virtualized a little faster than gigabit speeds between them.)
