Messages in this thread | | | Date | Wed, 14 Sep 2005 15:01:09 -0500 | From | Phil Dier <> | Subject | Slow I/O with SMP, Fusion-MPT and u160 SCSI JBOD |
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Hi,
I just tried the 2.6.14-rc1 kernel to see if it exhibits the behaviour I have described before[0]. It still does. Briefly, I have a dual Xeon 2.8 with 4GB ram, 1 adaptec and 1 fusion-mpt scsi device, each connected to 1 SCSI JBOD with 5 disks apiece[1]. I/O on scsi ids 0 and 1 both work flawlessly. I built an md device across ids 2 and 3, and the disks connected to the fusion-mpt are unbearably slow. This behaviour was not present in 2.6.12.3. When I partition the devices in question and mount a filesystem on them, they exhibit the same behaviour individually.
[0]: http://www.ussg.iu.edu/hypermail/linux/kernel/0508.3/1233.html [1]: http://www.icglink.com/debug-2.6.14-rc1.html
Here is what iostat looks like during what should be heavy I/O (my tesh.sh script described in [1] is running), showing only the relevant devices:
$ iostat 1 -k | awk '/(Device|md5|md6|md7)/{print $0;}' Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 0.62 0.00 2.46 244 198312 md6 0.62 0.00 2.46 228 198312 md7 0.61 0.01 2.45 440 197856 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 0.00 0.00 0.00 0 0 md6 0.00 0.00 0.00 0 0 md7 0.00 0.00 0.00 0 0 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 25.74 0.00 102.97 0 104 md6 25.74 0.00 102.97 0 104 md7 9.90 0.00 39.60 0 40 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 59.41 0.00 237.62 0 240 md6 60.40 3.96 237.62 4 240 md7 20.79 3.96 79.21 4 80 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 100.99 0.00 403.96 0 408 md6 100.99 0.00 403.96 0 408 md7 72.28 0.00 289.11 0 292 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 16242.57 0.00 64970.30 0 65620 md6 16242.57 0.00 64970.30 0 65620 md7 16230.69 0.00 64922.77 0 65572 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 0.00 0.00 0.00 0 0 md6 0.00 0.00 0.00 0 0 md7 0.00 0.00 0.00 0 0 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 1014.85 0.00 4059.41 0 4100 md6 1014.85 0.00 4059.41 0 4100 md7 1014.85 0.00 4059.41 0 4100 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 0.00 0.00 0.00 0 0 md6 0.00 0.00 0.00 0 0 md7 0.00 0.00 0.00 0 0 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 0.00 0.00 0.00 0 0 md6 0.00 0.00 0.00 0 0 md7 0.00 0.00 0.00 0 0 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 0.00 0.00 0.00 0 0 md6 0.00 0.00 0.00 0 0 md7 0.00 0.00 0.00 0 0 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 0.00 0.00 0.00 0 0 md6 0.00 0.00 0.00 0 0 md7 0.00 0.00 0.00 0 0 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 0.00 0.00 0.00 0 0 md6 0.00 0.00 0.00 0 0 md7 0.00 0.00 0.00 0 0 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 0.00 0.00 0.00 0 0 md6 0.00 0.00 0.00 0 0 md7 0.00 0.00 0.00 0 0 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 0.00 0.00 0.00 0 0 md6 0.00 0.00 0.00 0 0 md7 0.00 0.00 0.00 0 0 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 0.00 0.00 0.00 0 0 md6 0.00 0.00 0.00 0 0 md7 0.00 0.00 0.00 0 0 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 0.00 0.00 0.00 0 0 md6 0.00 0.00 0.00 0 0 md7 0.00 0.00 0.00 0 0 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 0.00 0.00 0.00 0 0 md6 0.00 0.00 0.00 0 0 md7 0.00 0.00 0.00 0 0 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 0.00 0.00 0.00 0 0 md6 0.00 0.00 0.00 0 0 md7 0.00 0.00 0.00 0 0 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 0.00 0.00 0.00 0 0 md6 0.00 0.00 0.00 0 0 md7 0.00 0.00 0.00 0 0 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 0.00 0.00 0.00 0 0 md6 0.00 0.00 0.00 0 0 md7 0.00 0.00 0.00 0 0 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 0.00 0.00 0.00 0 0 md6 0.00 0.00 0.00 0 0 md7 0.00 0.00 0.00 0 0 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 0.00 0.00 0.00 0 0 md6 0.00 0.00 0.00 0 0 md7 0.00 0.00 0.00 0 0 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 0.00 0.00 0.00 0 0 md6 0.00 0.00 0.00 0 0 md7 0.00 0.00 0.00 0 0 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 0.00 0.00 0.00 0 0 md6 0.00 0.00 0.00 0 0 md7 0.00 0.00 0.00 0 0 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 0.00 0.00 0.00 0 0 md6 0.00 0.00 0.00 0 0 md7 0.00 0.00 0.00 0 0 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 0.00 0.00 0.00 0 0 md6 0.00 0.00 0.00 0 0 md7 0.00 0.00 0.00 0 0 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 0.00 0.00 0.00 0 0 md6 0.00 0.00 0.00 0 0 md7 0.00 0.00 0.00 0 0 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 0.00 0.00 0.00 0 0 md6 0.00 0.00 0.00 0 0 md7 0.00 0.00 0.00 0 0 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 0.00 0.00 0.00 0 0 md6 0.00 0.00 0.00 0 0 md7 0.00 0.00 0.00 0 0 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 0.00 0.00 0.00 0 0 md6 0.00 0.00 0.00 0 0 md7 0.00 0.00 0.00 0 0 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 0.00 0.00 0.00 0 0 md6 0.00 0.00 0.00 0 0 md7 0.00 0.00 0.00 0 0 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 0.00 0.00 0.00 0 0 md6 0.00 0.00 0.00 0 0 md7 0.00 0.00 0.00 0 0 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 0.00 0.00 0.00 0 0 md6 0.00 0.00 0.00 0 0 md7 0.00 0.00 0.00 0 0 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 0.00 0.00 0.00 0 0 md6 0.00 0.00 0.00 0 0 md7 0.00 0.00 0.00 0 0 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 3298.02 0.00 13192.08 0 13324 md6 3298.02 0.00 13192.08 0 13324 md7 3298.02 0.00 13192.08 0 13324 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 0.00 0.00 0.00 0 0 md6 0.00 0.00 0.00 0 0 md7 0.00 0.00 0.00 0 0 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 0.00 0.00 0.00 0 0 md6 0.00 0.00 0.00 0 0 md7 0.00 0.00 0.00 0 0 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 0.00 0.00 0.00 0 0 md6 0.00 0.00 0.00 0 0 md7 0.00 0.00 0.00 0 0 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 2789.11 0.00 11156.44 0 11268 md6 2789.11 0.00 11156.44 0 11268 md7 2789.11 0.00 11156.44 0 11268 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 0.00 0.00 0.00 0 0 md6 0.00 0.00 0.00 0 0 md7 0.00 0.00 0.00 0 0 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 0.00 0.00 0.00 0 0 md6 0.00 0.00 0.00 0 0 md7 0.00 0.00 0.00 0 0 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn md5 0.00 0.00 0.00 0 0 md6 0.00 0.00 0.00 0 0 md7 0.00 0.00 0.00 0 0
Thanks for looking. Please cc me on replies.
--
Phil Dier (ICGLink.com -- 615 370-1530 x733)
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