Monitoring SAN storage performance
§For random IO, look at read and write service times from
# iostat –RDTl <interval> <# intervals>
Disks: xfers read write queue time
-------------- -------------------------------- ------------------------------------ ------------------------------------ -------------------------------------- ---------
%tm bps tps bread bwrtn rps avg min max time fail wps avg min max time fail avg min max avg avg serv
act serv serv serv outs serv serv serv outs time time time wqsz sqsz qfull
hdisk1 0.9 12.0K 2.5 0.0 12.0K 0.0 0.0 0.0 0.0 0 0 2.5 9.2 0.6 92.9 0 0 3.7 0.0 71.4 0.0 0.0 0.3 15:58:27
hdisk0 0.8 12.1K 2.6 119.4 12.0K 0.0 4.4 0.1 12.1 0 0 2.5 8.7 0.8 107.0 0 0 3.3 0.0 61.1 0.0 0.0 0.3 15:58:27
hdisk2 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 0.0 0.0 0.0 0.0 0 0 0.0 0.0 0.0 0.0 0.0 0.0 15:58:27
hdisk3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 0.0 0.0 0.0 0.0 0 0 0.0 0.0 0.0 0.0 0.0 0.0 15:58:27
hdisk4 66.4 58.9M 881.1 58.9M 28.8K 879.1 6.4 0.1 143.5 0 0 2.0 1.8 0.2 27.5 0 0 54.7 0.0 3.6S 48.0 5.0 746.8 15:58:27
hdisk6 66.3 51.1M 797.4 51.0M 24.5K 795.9 7.6 0.1 570.1 0 0 1.5 1.5 0.2 32.9 0 0 51.3 0.0 2.7S 41.0 6.0 678.5 15:58:27
hdisk5 61.9 55.9M 852.9 55.9M 28.5K 850.5 6.0 0.1 120.8 0 0 2.4 1.6 0.1 33.6 0 0 46.1 0.0 3.8S 39.0 5.0 714.7 15:58:27
hdisk7 58.3 55.4M 843.1 55.4M 21.2K 841.9 6.7 0.1 167.6 0 0 1.3 1.3 0.2 20.8 0 0 48.3 0.0 2.1S 40.0 5.0 734.8 15:58:27
hdisk8 42.6 53.5M 729.1 53.5M 3.4K 728.9 5.7 0.1 586.4 0 0 0.2 0.9 0.2 5.9 0 0 54.3 0.0 2.8S 39.0 4.0 687.8 15:58:27
hdisk10 44.1 37.1M 583.0 37.0M 16.9K 582.0 3.7 0.1 467.7 0 0 1.0 1.4 0.2 12.9 0 0 23.1 0.0 1.3S 13.0 2.0 465.0 15:58:27
§Misleading indicators of disk subsystem performance
►%tm_act (percent time active)
●Not meaningful for virtual disks, meaningful for real physical disks
►%iowait
●A measure of CPU idle while there are outstanding IOs
●
§IOPS, tps, and xfers all refer to the same thing
# topas –D
or just press D when in topas

topas
# nmon
then press D three times

nmon