iostat.1

<B>Digital的Unix操作系统VAX 4.2源码</B>

.\" SCCSID: @(#)iostat.1	6.4	8/29/89
.TH iostat 1
.SH Name
iostat \- report I/O statistics
.SH Syntax
.B iostat
[
.B \-c
] [
.B \-t 
] [ \fIdisknames\fR\ ] [ \fIinterval\fR\ ] [ \fIcount\fR\ ]
.SH Description
.NXR "iostat command"
.NXR "I/O statistics" "reporting"
.NXR "terminal" "reporting I/O statistics"
.NXR "disk" "reporting I/O statistics"
.NXA "iostat command" "netstat command"
.NXA "iostat command" "vmstat command"
.NXA "I/O statistics" "terminal"
.NXA "I/O statistics" "disk"
The
.PN iostat
command reports I/O statistics for terminals, disks and cpus.  For terminals
the number of input and output characters are counted.  
For disks the number
of 512 byte blocks per second and number of transfers per second are displayed.
For cpus, it provides the percentage of time the system has
spent in user mode, in user mode running low priority (niced) processes,
in system mode, and idling.  On multiprocessor systems these cpu statistics
represent a cumulative summary of all the cpus.
.PP
The optional
.I disknames
argument causes disk statistics to be displayed for the specified disks.
If this argument is not specified then disk statistics will be displayed
for the first 3 disks only.
.PP
The optional
.I interval
argument causes
.PN iostat
to report once each
.I interval
seconds.
The first report is for all time since a reboot and each
subsequent report is for the last interval only.
.PP
The optional
.I count
argument restricts the number of reports.
.SH Options
.IP \-c 5
Displays the percentage of time each cpu spent in user mode,
running low priority (nice'd) processes, in system mode, and
idling.
.IP \-t
Displays the number of characters read from and written to terminals.
.SH Examples
This example will cause cpu and disk statistics for the 5 disks ra0, ra1, 
ra2, ra3, and ra4.
.EX
     iostat ra0 ra1 ra2 ra3 ra4 
.EE
This example will cause cpu, terminal, and disk statistics for ra0 to be
displayed and updated every 2 seconds.
.EX
     iostat \-t ra0 2
.EE
.SH Files
.PN /dev/kmem
.br
.PN /vmunix
.SH See Also
vmstat(1), cpustat(1)