Originally posted by: Chtz

Hi All,

When i was checking one of the server's performance found below output from vmstat -v

OUtput:

vmstat -v
              3145728 memory pages
              3019216 lruable pages
                50497 free pages
                    2 memory pools
              2262978 pinned pages
                 80.0 maxpin percentage
                  3.0 minperm percentage
                 90.0 maxperm percentage
                  0.0 numperm percentage
                 1902 file pages
                  0.0 compressed percentage
                    0 compressed pages
                  0.0 numclient percentage
                 90.0 maxclient percentage
                 1902 client pages
                    0 remote pageouts scheduled
              9771310 pending disk I/Os blocked with no pbuf
             68591167 paging space I/Os blocked with no psbuf
                 1972 filesystem I/Os blocked with no fsbuf
                40058 client filesystem I/Os blocked with no fsbuf
                59879 external pager filesystem I/Os blocked with no fsbuf
                 98.3 percentage of memory used for computational pages
 

and vmstat with intervals are below:

vmstat -wtI 2 5

System configuration: lcpu=4 mem=12288MB ent=0.10

   kthr            memory                         page                       faults                 cpu             time
----------- --------------------- ------------------------------------ ------------------ ----------------------- --------
  r   b   p        avm        fre    fi    fo    pi    po    fr     sr    in     sy    cs us sy id wa    pc    ec hr mi se
  4   2   0   10019754      53564     1     0   787   144   153   6541   948   5409  3035 11 61 21  7  0.88 883.6 14:45:22
 10   0   0   10019766      54776     6   489   395   809  1012   8042   852   4601  2322  4 68 25  3  0.90 898.2 14:45:24
  1   0   0   10019766      54928     2    28    78   121   154   4431   207   8753  1650 32 31 36  1  0.31 308.7 14:45:26
  2   0   0   10019766      55322     4    47    65   173   262   1069   175  38579  1601 32 33 32  2  0.27 268.7 14:45:28
  4   1   0   10019780      53484     4     1   905     0     0      0  1019   2818  2998 41 18 35  6  0.34 337.5 14:45:30

Without changing the kernel parameters how to troubleshoot this issue. Also is this related to I/O bottleneck?

Iostat output says:

iostat

System configuration: lcpu=4 drives=9 ent=0.10 paths=36 vdisks=0

tty:      tin         tout    avg-cpu: % user % sys % idle % iowait physc % entc
          0.0          6.6               47.3  18.8   32.1      1.9   0.8  849.5

Disks:        % tm_act     Kbps      tps    Kb_read   Kb_wrtn
hdisk10          1.3      98.1      18.2   1625845706  64246700
hdisk11          0.3     195.7       6.7   1936882976  1432660904
hdisk14          0.2      88.4       4.2   928510788  594305860
hdisk18         17.3     4624.4     1005.6   57013958616  22618550532
hdisk16          0.9     190.2      12.2   1634475932  1641066008
hdisk13          0.2      70.0       2.8   808781236  397040512
hdisk17          0.2     178.5       1.2   1655344812  1418714364
hdisk15          0.2     464.4       3.3   7933227672  64342084
hdisk12          0.2      69.8       2.3   890986020  310596408

Can anyone suggest me how to clear the I/O blocks, If increasing the CPU units will clear the  I/O blocks?????

Originally posted by: AncientAIXer

This might help:

http://www.ibmsystemsmag.com/aix/tipstechniques/systemsmanagement/Paging,-Memory-and-I-O-Delays/?page=3