Oracle on RAID - IOwait problem

From: Calvin Lim <calvin-lim_at_mediaring.com>
Date: Thu, 04 May 2000 22:45:42 -0500
Message-Id: <10487.105019@fatcity.com>

Hi,

We've just put a 8.1.5 on a 2CPU Sun Solaris into production.

The machine is hooked on to a RAID5 storage device by Seek. Oracle datafiles are spread across 3 channels on the RAID. What i'm noticing is that the disk iowait is reaching incredible levels and top is reporting 0.0% idle for CPU states and 100M swaps.

We're currently suspecting that it could be 1. the RAID configuration thats giving problem, 2. some cron driven perl/DBI jobs that is pounding the Database too often too hard with inefficient queries.

Could 2. be a reason for extensive iowaits thats always hovers round the 85% mark. I need some advise on how one would go about troubleshooting such iowait related problems? Thanks very much.

Regards,
Calvin

load averages:  0.39,  0.43,  0.46                        22:19:30

74 processes: 71 sleeping, 1 running, 2 on cpu CPU states: 0.0% idle, 5.2% user, 8.5% kernel, 86.3% iowait, 0.0% swap Memory: 1024M real, 16M free, 100M swap in use, 1900M swap free

PID USERNAME THR PRI NICE SIZE RES STATE TIME CPU COMMAND

 2359 root       1  59    0 1944K 1080K sleep   0:03  2.40% sshd1
29216 oracle     1  58    0  832M  799M cpu0    1:50  2.12% oracle
 2383 oracle     1  58    0 2000K 1360K cpu2    0:00  1.24% top
29214 mrurl      1  53    2   13M 4840K run     0:54  0.98% ifmxTrigger
10591 oracle     1  60    0  834M  798M sleep 102:23  0.95% oracle
27178 oracle     1  38    0 2000K 1160K sleep   0:55  0.51% top
10360 oracle     1  60    0  832M  798M sleep 113:10  0.50% oracle
10362 oracle     1  60    0  832M  797M sleep 112:00  0.49% oracle
10366 oracle     1  60    0  832M  797M sleep 111:50  0.42% oracle
10364 oracle     1  60    0  832M  798M sleep 112:27  0.41% oracle
10368 oracle     1  60    0  832M  797M sleep 112:16  0.38% oracle
 2389 oracle     1  60    0  831M  799M sleep   0:00  0.19% oracle
10338 oracle     1  59    0  833M  794M sleep   3:01  0.15% oracle
10340 oracle     1  58    0  832M  794M sleep   4:40  0.14% oracle
 9341 oracle     1  48    0 8960K 2352K sleep   9:34  0.13% tnslsnr

Received on Thu May 04 2000 - 22:45:42 CDT