iowait problem

[littleKoala]

Hi,
I have a problem with iowait, iowait is always very high,
almost 99% all the time, and it is without any disk activity, here is some outputs:
# vmstat 120 10
kthr memory page faults cpu
----- ----------- ------------------------ ------------ -----------
r b avm fre re pi po fr sr cy in sy cs us sy id wa
1 1 51425 1546 0 0 0 24 70 0 314 356 272 5 4 2 89
1 0 51425 1542 0 0 0 0 0 0 327 782 374 1 2 0 97
1 0 51425 1540 0 0 0 0 0 0 325 746 373 1 1 0 98
1 1 51425 1540 0 0 0 0 0 0 367 1056 432 2 7 0 91
1 1 51425 1455 0 0 0 0 0 0 344 796 378 2 2 0 96
1 1 51426 1381 0 0 0 0 0 0 365 1119 439 4 7 0 89
1 1 51426 1243 0 0 0 0 0 0 338 923 387 4 2 0 94
1 1 51426 1129 0 0 0 0 0 0 333 842 381 3 2 0 95
1 1 51426 1089 0 0 0 0 0 0 366 1120 437 3 7 0 89
1 1 51426 171 0 7 0 0 0 0 351 801 411 4 3 0 93

# iostat 30 5
tty: tin tout avg-cpu: % user % sys % idle % iowait
0.0 7.5 1.0 1.5 0.0 97.6

Disks: % tm_act Kbps tps Kb_read Kb_wrtn
hdisk0 1.1 3.4 0.8 8 95
hdisk3 0.0 0.0 0.0 0 0
hdisk6 0.0 0.0 0.0 0 0
hdisk1 0.0 0.0 0.0 0 0
hdisk5 0.0 0.0 0.0 0 0
hdisk4 0.0 0.0 0.0 0 0
hdisk7 0.5 0.9 0.4 0 26
hdisk8 0.0 0.0 0.0 0 0
hdisk2 0.4 0.9 0.4 0 26

so, what could be the reason of this problem? I use AIX 4.3.3 and running netscape web server and sybase. sometimes
I can't access the webserver because maybe the cpu load avg
is more than 3.

any helps will be appreciated,thanks,.
cahya

 

[Morsing]

I looks like a network adapter problem but I'm definately not sure.
A CPU load of 3 (or 40) won't stop you from accessing the server.

It clearly show one process trying to access one (very slow) I/O device (like a tape or network adapter).

Cheers Henrik Morsing
Certified AIX 4.3 Systems Administration
& p690 Technical Support