Hello Bob,
Wednesday, April 15, 2009, 1:01:02 AM, you wrote:
BF> Today I updated the firmware on my StorageTek 2540 to the latest
BF> recommended version and am seeing radically difference performance
BF> when testing with iozone than I did in February of 2008. I am using
BF> Solaris 10 U5 with all the latest patches.
BF> This is the performance achieved (on a 32GB file) in February last
BF> year:
BF> KB reclen write rewrite read reread
BF> 33554432 64 279863 167138 458807 449817
BF> 33554432 128 265099 250903 455623 460668
BF> 33554432 256 265616 259599 451944 448061
BF> 33554432 512 278530 294589 522930 471253
BF> This is the new performance:
BF> KB reclen write rewrite read reread
BF> 33554432 64 76688 27870 552106 555438
BF> 33554432 128 103120 369527 538206 555049
BF> 33554432 256 355237 366563 534333 553660
BF> 33554432 512 379515 364515 535635 553940
BF> When using the 64KB record length, the service times are terrible. At
BF> first I thought that my drive array must be broken but now it seems
BF> like a change in the ZFS caching behavior (i.e. caching gone!):
BF> extended device statistics
BF> device r/s w/s kr/s kw/s wait actv svc_t %w %b
BF> sd0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0
BF> sd1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0
BF> sd2 1.3 0.3 6.8 2.0 0.0 0.0 1.7 0 0
BF> sd10 0.0 99.3 0.0 12698.3 0.0 32.2 324.5 0 97
BF> sd11 0.3 105.9 38.4 12753.3 0.0 31.8 299.9 0 99
BF> sd12 0.0 100.2 0.0 12095.9 0.0 26.4 263.8 0 82
BF> sd13 0.0 102.3 0.0 12959.7 0.0 31.0 303.4 0 94
BF> sd14 0.1 97.2 12.8 12291.8 0.0 30.4 312.0 0 92
BF> sd15 0.0 99.7 0.0 12057.5 0.0 26.0 260.8 0 80
BF> sd16 0.1 98.8 12.8 12634.3 0.0 31.9 322.1 0 96
BF> sd17 0.0 99.0 0.0 12522.2 0.0 30.9 312.0 0 94
BF> sd18 0.2 102.1 25.6 12934.1 0.0 29.7 290.4 0 90
BF> sd19 0.0 103.4 0.0 12486.3 0.0 32.0 309.1 0 97
BF> sd20 0.0 105.0 0.0 12678.3 0.0 32.1 305.6 0 98
BF> sd21 0.1 103.9 12.8 12501.7 0.0 31.2 299.6 0 96
BF> sd22 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0
BF> sd23 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0
BF> sd28 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0
BF> sd29 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0
BF> nfs1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0
BF> Notice that the peak performance with large block writes is much
BF> better than it was before but the peak performance with smaller writes
BF> is much worse. When doing the smaller writes, the performance meter
BF> shows little blips every 10 seconds or so.
BF> One change is that I had applied a firmware tweak from Joel Miller
BF> (apparently no longer at Sun) to tell the array to ignore cache sync
BF> commands (i.e. don't wait for disk). This updated firmware seems
BF> totally different so it is unlikely that the firmware tweak will work.
Well, you need to disable cache flushes on zfs side then (or make a
firmware change work) and it will make a difference.
--
Best regards,
Robert Milkowski
http://milek.blogspot.com
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