I need to know how to determine what my I/O wait is 
caused by.
Here is the output of sar, put simply.

00:00:03    %usr    %sys    %wio   %idle
01:00:01       6      29      53      12
02:00:00       6      26      55      13
03:00:00       6      21      59      14
04:00:02       4      16      79       1
05:00:02       6      23      71       0
06:00:01       3      11      81       4
07:00:00       1       9      58      32
08:00:00       1       8      40      51
08:20:00       0       4      37      59
08:40:00       0       1       5      94
09:00:00       0       1       2      96
09:20:00       2       2       2      94
09:40:00       0       0       9      90
10:00:00       2       1      19      78
10:20:01      22      13      58       7
10:40:02       8      13      76       3
11:00:01       0      13      82       5
11:20:01       0      12      84       4

Average        4      14      55      27

In here, you can see that % idle is very low
but it appears that the system has much processing
power available.  
I don't know how to determine if my io wait is due
to the system waiting for data across the network,
waiting on the tape drive, or both, or neither.

Can someone shed some light for me?
Thanks for your time.
patrick


Patrick Boyle   
ESRI Systems Administration
Voice:          [909] 793-2853  Ext. 1-1461
Numeric Pager:  [909] 777-2791  
E-mail:         PBoyle AT esri DOT com