Commit | Line | Data |
---|---|---|
e3758c96 C |
1 | .TH IOSTAT 1 |
2 | .UC 4 | |
3 | .SH NAME | |
4 | iostat \- report I/O statistics | |
5 | .SH SYNOPSIS | |
6 | .B iostat | |
7 | [ interval [ count ] ] | |
8 | .SH DESCRIPTION | |
9 | .I Iostat | |
10 | iteratively reports the number of characters read and written to terminals, | |
11 | and, for each disk, the number of seeks and transfers per second, | |
12 | and the milliseconds per average seek. | |
13 | It also gives the percentage of time the system has | |
14 | spent in user mode, in user mode running low priority (niced) processes, | |
15 | in system mode, and idling. | |
16 | .PP | |
17 | To compute this information, for each disk, seeks and data transfer completions | |
18 | and number of words transferred are counted; | |
19 | for terminals collectively, the number | |
20 | of input and output characters are counted. | |
21 | Also, each sixtieth of a second, | |
22 | the state of each disk is examined | |
23 | and a tally is made if the disk is active. | |
24 | From these numbers and given the transfer rates | |
25 | of the devices it is possible to determine | |
26 | average seek times for each device. | |
27 | .PP | |
28 | The optional | |
29 | .I interval | |
30 | argument causes | |
31 | .I iostat | |
32 | to report once each | |
33 | .I interval | |
34 | seconds. | |
35 | The first report is for all time since a reboot and each | |
36 | subsequent report is for the last interval only. | |
37 | .PP | |
38 | The optional | |
39 | .I count | |
40 | argument restricts the number of reports. | |
41 | .SH FILES | |
42 | /dev/kmem | |
43 | /vmunix | |
44 | .SH SEE ALSO | |
45 | vmstat(1) |