I've been fighting with some hardware raid 5 issues for the last 4 weeks, I'm finally seeing some progress using redhat's dac960 driver under 2.4 but it is very spotty. I am getting sequential write bursts of up to 200MB/s, but then for 3 or so seconds after that, there is zero disk i/o (however the disk is at 100% utilization even when no i/o is being done.. messed up counters?). I've attached output from iostat in 1 second intravls. The drives and the array are fine, no bad disks, no rebuilding volumes, no errors of any type... performance is just WAY spotty. My stripe width is 4 and my stripe size is 128k (I've tried tons and tons of different configs using different stripe sizes). The drives are Ultra320 10k and the raid card is a Mylex extremeRaid 2000 (DAC960 driver). Thanks, Ben
Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s rkB/s wkB/s avgrq-sz avgqu-sz await svctm %util ----------------------------------------------------------------------------------------------------------------------- rd/c0d1 0.00 33674.00 0.00 0.00 24.00 271808.00 12.00 135904.00 0.00 82.87 0.00 0.00 100.00 rd/c0d1 0.00 7899.00 0.00 0.00 8.00 63744.00 4.00 31872.00 0.00 403.70 0.00 0.00 100.00 rd/c0d1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 406.00 0.00 0.00 100.00 rd/c0d1 0.00 45182.00 0.00 0.00 8.00 364544.00 4.00 182272.00 0.00 495.76 0.00 0.00 100.00 rd/c0d1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 793.00 0.00 0.00 100.00 rd/c0d1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 793.00 0.00 0.00 100.00 rd/c0d1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 793.00 0.00 0.00 100.00 rd/c0d1 0.00 0.00 0.00 0.00 0.00 8.00 0.00 4.00 0.00 793.81 0.00 0.00 100.00 rd/c0d1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 794.00 0.00 0.00 100.00 rd/c0d1 0.00 24051.00 0.00 0.00 16.00 194128.00 8.00 97064.00 0.00 836.10 0.00 0.00 100.00 rd/c0d1 0.00 1490.00 0.00 0.00 8.00 12032.00 4.00 6016.00 0.00 1023.86 0.00 0.00 100.00 rd/c0d1 0.00 94152.00 0.00 0.00 0.00 760480.00 0.00 380240.00 0.00 1418.98 0.00 0.00 100.00 rd/c0d1 0.00 645.00 0.00 0.00 0.00 5192.00 0.00 2596.00 0.00 1937.22 0.00 0.00 100.00 rd/c0d1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1938.00 0.00 0.00 100.00 rd/c0d1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1938.00 0.00 0.00 100.00 rd/c0d1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1938.00 0.00 0.00 100.00 rd/c0d1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1938.00 0.00 0.00 100.00 rd/c0d1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1938.00 0.00 0.00 100.00 rd/c0d1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1938.00 0.00 0.00 100.00 rd/c0d1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1938.00 0.00 0.00 100.00 rd/c0d1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1938.00 0.00 0.00 100.00 rd/c0d1 0.00 15739.00 0.00 0.00 16.00 127072.00 8.00 63536.00 0.00 1981.42 0.00 0.00 100.00 rd/c0d1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2085.00 0.00 0.00 100.00 rd/c0d1 0.00 14260.00 0.00 0.00 8.00 115104.00 4.00 57552.00 0.00 2157.40 0.00 0.00 100.00 rd/c0d1 0.00 19798.00 0.00 0.00 0.00 159744.00 0.00 79872.00 0.00 2249.54 0.00 0.00 100.00 rd/c0d1 0.00 12687.00 0.00 0.00 8.00 102400.00 4.00 51200.00 0.00 2398.09 0.00 0.00 100.00 rd/c0d1 0.00 24160.00 0.00 0.00 8.00 195840.00 4.00 97920.00 0.00 2786.77 0.00 0.00 100.00 rd/c0d1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 40130.67 0.00 0.00 100.00 rd/c0d1 0.00 26512.00 0.00 0.00 0.00 213832.00 0.00 106916.00 0.00 3010.01 0.00 0.00 100.00 rd/c0d1 0.00 509.00 0.00 0.00 0.00 4096.00 0.00 2048.00 0.00 3036.69 0.00 0.00 100.00 rd/c0d1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3039.00 0.00 0.00 100.00 rd/c0d1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3039.00 0.00 0.00 100.00 rd/c0d1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3039.00 0.00 0.00 100.00 rd/c0d1 0.00 14234.00 0.00 0.00 0.00 114856.00 0.00 57428.00 0.00 3146.79 0.00 0.00 100.00 rd/c0d1 0.00 15182.00 0.00 0.00 8.00 122888.00 4.00 61444.00 0.00 3191.96 0.00 0.00 100.00 rd/c0d1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3342.00 0.00 0.00 100.00 rd/c0d1 0.00 32507.00 0.00 0.00 8.00 262312.00 4.00 131156.00 0.00 3559.97 0.00 0.00 100.00 rd/c0d1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3625.00 0.00 0.00 100.00 rd/c0d1 0.00 55.00 0.00 0.00 0.00 448.00 0.00 224.00 0.00 3625.63 0.00 0.00 100.00
