High %wio problem

Hi all,

Quick question regarding high %wio. Every month we get a day where the %wio is so high it brings the Oracle server to a crawl so I'm wondering what the reasons are that can cause this (eliminated insufficient rollback segments, tablespace sizes, and archiving of redo logs). Restarting Oracle cures the %wio back to normal.

We have Oracle 8.1.5 EE running on Solaris 7 (5x9Gb disks, raid 5) and have a 10Gb database.

Thanks in advance, Dave Weeks.

And here's the output of the 'sar' utility over a typical problem day:

00:00:01   %usr   %sys  %wio  %idle
01:00:01       0       0       1      99
02:00:02       0       0       1      99
03:00:01       1       2       2      98
04:00:01       0       0       6      94
05:00:02       0       0       2      98
06:00:01       0       0       1      98
07:00:01       0       0       1      98
08:00:01       0       0       1      98
08:20:01       0       0       1      99
08:40:01       0       0       2      97
09:00:00       0       0       1      98
09:20:01       0       0       1      99
09:40:00       1       1       7      90
10:00:01       0       0       2      98
10:20:01       0       0       3      97
10:40:01       1       1       4      94
11:00:01       0       0       2      98
11:20:01       1       1       6      92
11:40:01       1       0       3      96
12:00:01       0       1       5      93
12:20:01       0       1       3      96
12:40:01       0       0       2      98
13:00:01       0       0       2      98
13:20:01       0       0       2      98
13:40:03       0       8      23      68
14:00:25       0       7      14      79
14:20:03       0       8      18      75
14:40:10       1       9      20      70
15:00:02       0       7      16      76
15:20:04       0       7      15      78
15:40:03       0       7      14      79
16:00:29       0       8      17      75
16:23:58       1      10      34      54
16:40:06       2      16      65      18

Average        0       2       9      89