/proc/diskstats reports incorrect values for inflight I/O count on RHEL 5

Solution Unverified - Updated -

Issue

  • iostat reports large incorrect values for the 'avgqu-sz' field
avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           2.26    0.00    1.67    0.05    0.00   96.02

Device:         rrqm/s   wrqm/s   r/s   w/s   rsec/s   wsec/s avgrq-sz avgqu-sz   await  svctm  %util
sdbc              0.00     0.00 172.80 18.10 17691.20   328.80    94.39     0.87    4.58   1.37  26.10
sdbc1             0.00     0.00 172.80 18.10 17691.20   328.80    94.39 1844674407370950.00    4.58   5.17  98.61
sdbm              0.10     0.00 140.50 21.50 14083.20   505.60    90.05     0.83    5.10   1.44  23.35
sdbm1             0.10     0.00 140.50 21.50 14083.20   505.60    90.05 1844674407370954.75    5.10   5.72  92.69
sdae              0.00     0.00 217.30  8.30 20627.20   204.80    92.34     0.84    3.72   1.40  31.48
sdae1             0.00     0.00 217.30  8.30 20627.20   204.80    92.34 1844674407370952.00    3.72   4.28  96.47
sdbl1             0.00     0.00  0.00  0.00     0.00     0.00     0.00 18264103043276780.00    0.00   0.00 101.58
sdch1             0.00     0.00  0.00  0.00     0.00     0.00     0.00 614891469123650.75    0.00   0.00 100.00
  • /proc/diskstats shows incorrect values for the inflight (3rd last) column, which should be in the range of 0 to a small positive value:
$ grep sdbed1 /proc/diskstats 
 132 1489 sdbed1 2846444 42114 333393473 23418958 362917 33506 52398741 12505314 4294967295 1648968319 2676043672

Environment

  • RHEL 5
  • sysstat v7

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