System activity reporting

System activity reporting is a performance analysis tool. As various system actions occur, counters in the operating system are incremented to keep track of them. The following system activities are tracked:

• central processing unit (CPU) utilization

• buffer usage

• disk and tape input/output activity

• terminal device activity

• system call activity

• switching

• file access

• queue activity

• kernel tables

• interprocess communication

• paging

• free memory and swap space

• kernel memory allocation (KMA)

System activity data can be accessed on a special request basis using the sar(ADM) command, or it can be saved automatically on a routine basis using the sadc(ADM) command and the shell scripts sa1 and sa2. Generally, the demand system activity reports pinpoint specific performance problems, while the automatic reports are generated to monitor system performance.

The system activity reporting tools include the following commands. (Note that the sadc, sa1, and sa2 commands are run by other commands or through cron; they are not designed to be run from a shell command line.)

sadc

samples and saves the system activity data. Results are saved in binary format.

sar

Calls sadc or uses files created by sadc to sample cumulative activity counters internal to the system and provides reports on various system-wide activities.

sa1

collects and stores data in binary file /var/adm/sa/sadd, where dd is the current day. This is a shell script.

sa2

writes a daily report in file /var/adm/sa/sardd, where dd is the current day. This is a shell script.