sadc.8

linux下查看系统工具原码,如IOSTAT等

.TH SADC 8 "OCTOBER 2005" Linux "Linux User's Manual" -*- nroff -*-
.SH NAME
sadc \- System activity data collector.
.SH SYNOPSIS
.B /usr/lib/sa/sadc [ -d ] [ -F ] [ -I ] [ -L ] [ -V ] [
.I interval
.B [
.I count
.B ] ] [
.I outfile
.B ]
.SH DESCRIPTION
The
.B sadc
command samples system data a specified number of times (
.I count
) at a specified interval measured in seconds (
.I interval
). It writes in binary format to the specified
.I outfile
or to the standard output. If
.I outfile
is set to -, then
.B sadc
uses the standard system activity daily data file, the
.IR /var/log/sa/sa dd
file, where the dd parameter indicates the current day.
By default
.B sadc
collects all the data available from the kernel.
Exceptions are interrupts and disks data, for which the
relevant options must be explicitly passed to
.B sadc
(see options below).

When the
.I count
parameter is not specified,
.B sadc
writes its data endlessly.
When both
.I interval
and
.I count
are not specified, a dummy record, which is used at system startup to mark
the time when the counter restarts from 0, will be written.
For example, one of the system startup script may write the restart mark to
the daily data file by the command entry:

.B "/usr/lib/sa/sadc -"

The
.B sadc
command is intended to be used as a backend to the
.B sar
command.

Note: The
.B sadc
command only reports on local activities.

.SH OPTIONS
.IP -d
Tell
.B sadc
to report statistics for disks. By default
.B sadc
does not report disks activity to prevent data files from growing too large.
.IP -F
The creation of
.I outfile
will be forced. If the file already exists and has not the format expected by
.B sadc
then it will be truncated. This may be particularly useful for daily data files
created by an older version of sadc and whose format is no longer compatible
with current one.
.IP -I
Tell
.B sadc
to report statistics for all system interrupts. By default
.B sadc
only reports statistics for the total number of interrupts.
.IP -L
.B sadc
will try to get an exclusive lock on the
.I outfile
before writing to it or truncating it. Failure to get the lock is fatal,
except in the case of trying to write a normal (i.e. not a dummy and not
a header) record to an existing file, in which case
.B sadc
will try again at the next interval. Usually, the only reason a lock
would fail would be if another
.B sadc
process were also writing to the file. This can happen when cron is used
to launch
.B sadc .
If the system is under heavy load, an old
.B sadc
might still be running when cron starts a new one. Without locking,
this situation can result in a corrupted system activity file.
.IP -V
Print version number then exit.

.SH EXAMPLES
.B /usr/lib/sa/sadc 1 10 /tmp/datafile
.RS
Write 10 records of one second intervals to the /tmp/datafile binary file.
.SH BUGS
.I /proc
filesystem must be mounted for the
.B sadc
command to work.

All the statistics are not necessarily available, depending on the kernel version used.
.SH FILES
.IR /var/log/sa/sa dd
.RS
Indicate the daily data file, where the
.B dd
parameter is a number representing the day of the month.

.RE
.IR /proc
contains various files with system statistics.
.SH AUTHOR
Sebastien Godard (sysstat <at> wanadoo.fr)
.SH SEE ALSO
.BR sar (1),
.BR sa1 (8),
.BR sa2 (8),
.BR sadf (1),
.BR mpstat (1),
.BR iostat (1),
.BR vmstat (8)

.I http://perso.wanadoo.fr/sebastien.godard/