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System Administration Guide

How to Check Terminal Activity (sar)

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


$ sar -y
SunOS saturn 5.6 prefcs3 sun4c   08/20/96
00:00:03 rawch/s canch/s outch/s rcvin/s xmtin/s mdmin/s
01:00:02       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 Table 64-20.

Table 64-20 Output From the sar -y Command

Field Name 

Description 

rawch/s

Input characters (raw queue), per second 

canch/s

Input characters 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, and 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 example shows output from the sar -y command. 


$ sar -y
SunOS venus 5.6 Generic sun4m    08/20/96
14:28:12 rawch/s canch/s outch/s rcvin/s xmtin/s mdmin/s
14:29:12       0       1     157       1       3       0
14:30:12       0       2      34       2       2       0
14:31:12       0       1      11       1       2       0
 
Average        0       1      67       1       2       0