Solaris Application Programming, 1/e - Chapter 4 - Parent Directory

68 Chapter 4 Informational Tools
The command to read an existing sar output file is shown in Example 4.22.
Example 4.22 Command Line to Instruct sar to Read an Existing Data File
$ sar -A -f /tmp/sar.dat
This asks sar to output all (-A) the information from the sar archive (/tmp/
sar.dat). It is possible to request that sar output only a subset of counters.
In the sar output shown in Example 4.21, it is apparent that the CPU is 50%
busy (in fact, it is a two-CPU system, and one CPU is busy compiling an application),
and that there is some character output and some read and write system
calls. It is reasonably apparent that the system is CPU-bound, although it has
additional CPU resources which could potentially be used to do more work.
4.3.10 Reporting I/O Activity (iostat)
The iostat utility is very similar to vmstat, except that it reports I/O activity
rather than memory statistics.
The first line of output from iostat is the activity since boot. Subsequent lines
represent the activity over the time interval between reports. Example output
from iostat is shown in Example 4.23.
The information is as follows.
Example 4.23 Example of iostat Output
% iostat 1
tty ssd0 ssd1 nfs1 nfs58 cpu
tin tout kps tps serv kps tps serv kps tps serv kps tps serv us sy wt id
0 2 17 1 90 22 1 45 0 0 0 0 0 27 20 1 0 79
0 234 0 0 0 8 1 6 0 0 0 0 0 0 50 2 0 48
0 80 0 0 0 0 0 0 0 0 0 0 0 0 50 0 0 50
0 80 0 0 0 560 4 16 0 0 0 0 0 0 46 2 1 50
0 80 0 0 0 352 4 13 0 0 0 0 0 0 48 8 0 44
0 80 0 0 0 560 15 13 0 0 0 0 0 0 42 6 2 50
The first two columns give the number of characters read (tin) and written
(tout) for the tty devices.
The next four sets of three columns give information for four disks. The kps
column lists the number of kilobytes per second, tps the number of transfers
per second, and serv the average service time in ms.
CPU time is reported as a percentage in user (us), system (sy), waiting for I/O
(wt), and idle (id).