AIX 5L Problem Determination - IBM Redbooks

of times spaced at the specified intervals in seconds. If you suspect an I/O-bound
system, run the command in the example:
# sar -d 1 1
AIX server4 1 5 00015F8F4C00 08/28/02
10:00:42 device %busy avque r+w/s blks/s avwait avserv
10:00:43 -2147483648 0.0 -2147483648 -2147483648 0.0
0.0
-2147483648 0.0 -2147483648 -2147483648 0.0
0.0
-2147483648 0.0 -2147483648 -2147483648 0.0
0.0
-2147483648 0.0 -2147483648 -2147483648 0.0
0.0
-2147483648 0.0 -2147483648 -2147483648 0.0
0.0
-2147483648 0.0 -2147483648 -2147483648 0.0
0.0
-2147483648 0.0 -2147483648 -2147483648 0.0
0.0
The -d flag reports activity for each block device (for example, disk or tape drive),
with the exception of XDC disks and tape drives. When data is displayed, the
device specification disk is generally used to represent a disk drive. The device
specification used to represent a tape drive is machine dependent. The activity
data reported is as follows. The following reports the portion of time the device
was busy servicing a transfer request, and the average number of requests
outstanding during that time.
%busy, avque
The following reports the number of read/write transfers from or to a device. The
number of bytes is transferred in 512-byte units.
read/s, write/s, blks/s
The following reports the number of milliseconds per average seek:
avseek
10.4 Network I/O bound system
When performance problems arise, your system might be totally innocent, while
the real culprit is buildings away. An easy way to tell if the network is affecting
overall performance is to compare those operations that involve the network with
Chapter 10. Performance problem determination 265