System Administration Guide: Advanced Administration

How to Check Terminal Activity (sar -y)

Use the sar -y command to monitor terminal device activities.


$ sar -y
00:00:00 rawch/s canch/s outch/s rcvin/s xmtin/s mdmin/s
01:00:00       0       0       0       0       0       0

If you have a lot of terminal I/O, you can use this report to determine if there are any bad lines. The activities recorded are defined in the following table.

Table 24–20 Output From the sar -y Command

Field Name 

Description 

rawch/s

Input characters (raw queue), per second 

canch/s

Input characters that are processed by canon (canonical queue), per second 

outch/s

Output characters (output queue) per second 

rcvin/s

Receiver hardware interrupts per second 

xmtin/s

Transmitter hardware interrupts per second 

mdmin/s

Modem interrupts per second 

The number of modem interrupts per second (mdmin/s) should be close to zero. The receive and transmit interrupts per second (xmtin/s and rcvin/s) should be less than or equal to the number of incoming or outgoing characters, respectively. If this is not the case, check for bad lines.

Example—Checking Terminal Activity

The following abbreviated example shows output from the sar -y command.


$ sar -y
SunOS venus 5.9 Generic sun4u    06/24/2001

00:00:00 rawch/s canch/s outch/s rcvin/s xmtin/s mdmin/s
01:00:00       0       0       0       0       0       0
02:00:02       0       0       0       0       0       0
03:00:00       0       0       0       0       0       0
04:00:00       0       0       0       0       0       0
05:00:01       0       0       0       0       0       0
06:00:00       0       0       0       0       0       0
07:00:00       0       0       0       0       0       0
08:00:01       0       0       0       0       0       0
08:20:00       0       0       0       0       0       0
08:40:00       0       0       0       0       0       0
09:00:00       0       0       0       0       0       0
09:20:00       0       0       0       0       0       0
09:40:00       0       0       0       0       0       0
10:00:00       0       0       0       0       0       0
10:20:00       0       0       0       0       0       0
10:40:01       0       0      20       0       0       0

Average        0       0       3       0       0       0