When using the latest iostat in the sysstat package in the RHEL 3 U3 beta (sysstat-4.0.7-4.EL3.3.i386.rpm), I get very inaccurate readings. Steps to reproduce: in a term, start a dd command such as the following: # dd if=/dev/hda1 of=/dev/null bs=8k In another term, run the following command. # iostat -x 1 5 I got results such as the following: Linux 2.4.21-15.0.3.EL (halfsquatch.mine.nu) 07/31/2004 avg-cpu: %user %nice %sys %idle 3.01 0.09 0.61 96.29 Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s rkB/s wkB/s avgrq-sz avgqu-sz await svctm %util /dev/hda 3.81 3.88 2.07 2.40 35.07 50.25 17.54 25.13 19.08 1.46 66.21 41.33 18.49 /dev/hda1 0.21 0.01 0.03 0.00 1.91 0.10 0.96 0.05 54.10 0.01 30.81 8.28 0.03 /dev/hda2 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 9.43 0.00 15.68 14.86 0.00 /dev/hda3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 10.77 0.00 17.27 15.91 0.00 /dev/hda5 1.61 3.21 1.00 1.85 20.88 40.54 10.44 20.27 21.60 0.56 19.77 3.39 0.97 /dev/hda6 0.02 0.04 0.10 0.02 0.90 0.49 0.45 0.24 11.46 0.09 72.49 7.70 0.09 /dev/hda7 0.04 0.04 0.07 0.01 0.69 0.28 0.35 0.14 11.91 0.16 194.26 18.63 0.15 /dev/hda8 0.00 0.58 0.84 0.51 6.76 8.84 3.38 4.42 11.51 2.13 156.86 10.60 1.44 avg-cpu: %user %nice %sys %idle 33.33 0.00 66.67 0.00 Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s rkB/s wkB/s avgrq-sz avgqu-sz await svctm %util /dev/hda 89066.67 1600.00 6933.33 266.67 771733.33 15466.67 385866.67 7733.33 109.33 1431639872.00 29.07 4.72 3400.00 /dev/hda1 86000.00 0.00 5733.33 0.00 733866.67 0.00 366933.33 0.00 128.00 753.33 12.56 5.93 3400.00 /dev/hda2 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 /dev/hda3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 /dev/hda5 3066.67 1133.33 1133.33 233.33 37333.33 11200.00 18666.67 5600.00 35.51 1893.33 89.27 14.63 2000.00 /dev/hda6 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 /dev/hda7 0.00 466.67 66.67 33.33 533.33 4266.67 266.67 2133.33 48.00 160.00 153.33 160.00 1600.00 /dev/hda8 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 avg-cpu: %user %nice %sys %idle 0.00 0.00 100.00 0.00 Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s rkB/s wkB/s avgrq-sz avgqu-sz await svctm %util /dev/hda 14333.33 0.00 3866.67 100.00 143733.33 266.67 71866.67 133.33 36.30 1431641215.33 110.25 8.40 3333.33 /dev/hda1 9000.00 0.00 600.00 0.00 76800.00 0.00 38400.00 0.00 128.00 680.00 120.00 55.56 3333.33 /dev/hda2 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 /dev/hda3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 /dev/hda5 5300.00 0.00 3233.33 33.33 66400.00 0.00 33200.00 0.00 20.33 2956.67 107.14 10.20 3333.33 /dev/hda6 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 /dev/hda7 33.33 0.00 33.33 66.67 533.33 266.67 266.67 133.33 8.00 146.67 153.33 96.67 966.67 /dev/hda8 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 avg-cpu: %user %nice %sys %idle 66.67 0.00 33.33 0.00 Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s rkB/s wkB/s avgrq-sz avgqu-sz await svctm %util /dev/hda 13500.00 0.00 3900.00 0.00 139466.67 0.00 69733.33 0.00 35.76 1431641215.33 91.37 8.55 3333.33 /dev/hda1 7000.00 0.00 466.67 0.00 59733.33 0.00 29866.67 0.00 128.00 670.00 135.00 71.43 3333.33 /dev/hda2 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 /dev/hda3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 /dev/hda5 6500.00 0.00 3433.33 0.00 79733.33 0.00 39866.67 0.00 23.22 3113.33 85.44 9.71 3333.33 /dev/hda6 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 /dev/hda7 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 /dev/hda8 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 avg-cpu: %user %nice %sys %idle 66.67 0.00 33.33 0.00 Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s rkB/s wkB/s avgrq-sz avgqu-sz await svctm %util /dev/hda 13966.67 0.00 3133.33 0.00 135466.67 0.00 67733.33 0.00 43.23 1431639972.00 90.32 10.64 3333.33 /dev/hda1 9000.00 0.00 600.00 0.00 76800.00 0.00 38400.00 0.00 128.00 670.00 115.00 55.56 3333.33 /dev/hda2 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 /dev/hda3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 /dev/hda5 4966.67 0.00 2533.33 0.00 58666.67 0.00 29333.33 0.00 23.16 1870.00 84.47 13.16 3333.33 /dev/hda6 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 /dev/hda7 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 /dev/hda8 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 The following is the /proc/partitions that correlates to this: major minor #blocks name rio rmerge rsect ruse wio wmerge wsect wuse running use aveq 3 0 39070080 hda 319521 588928 5414712 6005840 371059 598820 7758892 39715700 4294967243 28541241 22526844 3 1 10236208 hda1 5040 31832 294634 58270 680 1137 14680 117940 2 47320 176290 3 2 151200 hda2 51 260 622 350 23 14 76 810 0 1100 1160 3 3 158760 hda3 34 188 444 290 10 5 30 470 0 700 760 3 4 1 hda4 3 0 6 0 0 0 0 0 0 0 0 3 5 8195008 hda5 153859 249028 3223106 2122090 285214 496175 6259832 6557500 0 1489970 8690410 3 6 8187448 hda6 14919 2438 138490 140530 3751 5588 75512 1212870 0 143830 1374890 3 7 10447888 hda7 10678 6372 107282 2218330 1995 6042 43698 243660 0 236040 2461990 3 8 1693408 hda8 129931 576 1043648 1250700 79386 89859 1365064 31582450 0 2219360 32868000 The following is the /proc/stat that correlates to this: cpu 463976 14178 94594 14866491 270797 27888 2303 cpu0 463976 14178 94594 14866491 270797 27888 2303 page 2707894 3879457 swap 130430 170633 intr 40115749 15740227 194708 0 2 2 2 6 2 4 2 2 9945787 4106149 0 690638 9438218 disk_io: (3,0):(693251,319529,5414712,373722,7758892) ctxt 55391583 btime 1091091959 processes 31370 procs_running 2 procs_blocked 1 The %util is extraordinarlily high but other readings also seem inaccurate. This has reproduced on every system I have tried.
Created attachment 102332 [details] The /proc/stat as a file. Adding /proc/stat as a file...
Created attachment 102333 [details] The /proc/partitions file. Adding /proc/partitions file...
*** This bug has been marked as a duplicate of 134579 ***
A fix for this problem was committed to the RHEL3 U6 patch pool on 22-Apr-2005 (in kernel version 2.4.21-32.2.EL). *** This bug has been marked as a duplicate of 134579 ***
An advisory has been issued which should help the problem described in this bug report. This report is therefore being closed with a resolution of ERRATA. For more information on the solution and/or where to find the updated files, please follow the link below. You may reopen this bug report if the solution does not work for you. http://rhn.redhat.com/errata/RHSA-2005-663.html