Analysis of top output

[William Muriithi]

Hi there,

I was fishing around for the cause of server slowdown and I realized I
may be very conversant with some of top's data. Well, I do have some
assumption but wonder if they are right. 2 of them are of particular
interest to me:-

iowait
I googled a bit on what this could entail and it looks like something
to do with disk access. Now, the tricky bit is, I haven't installed
anything new recently that could need intensive hard disk access. I
have tried using lsof /dev/sda1, but it don't seem to be very helpful.
Any pointer on how one can nail the offending process  - well, other
than using lsof against all existing process?

0k shrd
The other data I don't understand is shrd. Would one of us be aware of
what this data means?

Sample output of top below

07:06:32  up 18 days, 16:19,  1 user,  load average: 6.58, 5.51, 4.46
141 processes: 140 sleeping, 1 running, 0 zombie, 0 stopped
CPU states:  cpu    user    nice  system    irq  softirq  iowait    idle
           total    3.0%    0.0%    1.1%   0.1%     0.0%   95.3%    0.0%
           cpu00    3.1%    0.0%    0.9%   0.0%     0.0%   95.8%    0.0%
           cpu01    3.0%    0.0%    1.4%   0.4%     0.2%   94.8%    0.2%
Mem:  2061424k av, 1936696k used,  124728k free,       0k shrd,   27348k buff
                   1482172k actv,  189004k in_d,   29920k in_c
Swap: 2096440k av, 1709540k used,  386900k free                  106656k cached

  PID USER     PRI  NI  SIZE  RSS SHARE STAT %CPU %MEM   TIME CPU COMMAND
 2504 amavis    16   0 50324  40M  2272 S     0.5  1.9   0:09   0 amavisd
 4907 amavis    15   0 44648  34M  2272 S     0.4  1.7   0:00   0 amavisd
 3118 amavis    15   0 49452  39M  2272 S     0.2  1.9   0:06   1 amavisd
    1 root      15   0   504  476   448 S     0.0  0.0   0:12   1 init
    2 root      RT   0     0    0     0 SW    0.0  0.0   0:00   0 migration/0
    3 root      RT   0     0    0     0 SW    0.0  0.0   0:00   1 migration/1
    4 root      15   0     0    0     0 SW    0.0  0.0   0:00   1 keventd
    5 root      34  19     0    0     0 SWN   0.0  0.0   0:00   0 ksoftirqd/0
    6 root      34  19     0    0     0 SWN   0.0  0.0   0:00   1 ksoftirqd/1
    9 root      25   0     0    0     0 SW    0.0  0.0   0:00   1 bdflush
    7 root      15   0     0    0     0 SW    0.0  0.0   9:27   0 kswapd
    8 root      15   0     0    0     0 SW    0.0  0.0   7:02   1 kscand
   10 root      15   0     0    0     0 SW    0.0  0.0   0:11   1 kupdated
Continues.............

Regards,
William
--
The Toronto Linux Users Group.      Meetings: http://gtalug.org/
TLUG requests: Linux topics, No HTML, wrap text below 80 columns
How to UNSUBSCRIBE: http://gtalug.org/wiki/Mailing_lists