Section: Linux User's Manual (8)
Updated: JUNE 2006
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sadc - System activity data collector.
/usr/lib/sa/sadc [ -d ] [ -F ] [ -I ] [ -L ] [ -V ] [
] ] [
command samples system data a specified number of times (
) at a specified interval measured in seconds (
). It writes in binary format to the specified
or to the standard output. If
is set to -, then
uses the standard system activity daily data file, the
file, where the dd parameter indicates the current day.
collects all the data available from the kernel.
Exceptions are interrupts and disks data, for which the
relevant options must be explicitly passed to
(see options below).
parameter is not specified,
writes its data endlessly.
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:
command is intended to be used as a backend to the
command only reports on local activities.
to report statistics for disks. By default
does not report disks activity to prevent data files from growing too large.
The creation of
will be forced. If the file already exists and has not the format expected by
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.
to report statistics for all system interrupts. By default
only reports statistics for the total number of interrupts.
will try to get an exclusive lock on the
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
will try again at the next interval. Usually, the only reason a lock
would fail would be if another
process were also writing to the file. This can happen when cron is used
If the system is under heavy load, an old
might still be running when cron starts a new one. Without locking,
this situation can result in a corrupted system activity file.
Print version number then exit.
command takes into account the following environment variable:
If this variable exists and its value is
will save its data in UTC time.
will also use UTC time instead of local time to determine the current
daily data file located in the
/usr/lib/sa/sadc 1 10 /tmp/datafile
Write 10 records of one second intervals to the /tmp/datafile binary file.
filesystem must be mounted for the
command to work.
All the statistics are not necessarily available, depending on the kernel version used.
contains various files with system statistics.
Indicate the daily data file, where the
parameter is a number representing the day of the month.
Sebastien Godard (sysstat <at> wanadoo.fr)
- SEE ALSO
linux.jgfs.net manual pages