> from:dong wu >I have made a test in my server! >raid5 capacity:80G, disks:9 >IO type IOPS speed(M/s) >1024k seq write 40.67 40.67 >512k seq write 70.89 39.45 >256k seq write 36.02 34.00 >128k seq write 134.19 16.77 >64k seq write 232.26 14.52 >32k seq write 160.23 5.01 >16k seq write 148.48 2.32 >8k seq write 151.05 1.18 >4k seq write 151.39 0.59 >2k seq write 290.90 0.57 >1k seq write 526.21 0.51 >512B seq write 1076.60 0.53 > >I don't know why raid5 seq write is so slow. >Does delaying write cause this? > well, (1) is raid5 degraded ,recovering or resyncing ? (2) how is the speed of members ? (3) how do you test that (tools) and how is the cpu utilization during test? (4) it seems that you used partitions of disks as raid members, any other read/write operations on other partitions ? (5) try to set /sys/block/mdX/md/stripe_cache_size larger (6) XOR calculation too slow? ------------------ spren.gm@xxxxxxxxx 2010-01-08 -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
