The
sadc
command samples system data a specified number of times (
count
) at a specified interval measured in seconds (
interval
). It writes in binary format to the specified
outfile
or to the standard output. If
outfile
is set to -, then
sadc
uses the standard system activity daily data file, the
/var/log/sa/sadd
file, where the dd parameter indicates the current day.
By default
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
sadc
(see options below).
When the
count
parameter is not specified,
sadc
writes its data endlessly.
When both
interval
and
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:
/usr/lib/sa/sadc -
The
sadc
command is intended to be used as a backend to the
sar
command.
Note: The
sadc
command only reports on local activities.
OPTIONS
-d
Tell
sadc
to report statistics for disks. By default
sadc
does not report disks activity to prevent data files from growing too large.
-F
The creation of
outfile
will be forced. If the file already exists and has not the format expected by
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.
-I
Tell
sadc
to report statistics for all system interrupts. By default
sadc
only reports statistics for the total number of interrupts.
-L
sadc
will try to get an exclusive lock on the
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
sadc
will try again at the next interval. Usually, the only reason a lock
would fail would be if another
sadc
process were also writing to the file. This can happen when cron is used
to launch
sadc .
If the system is under heavy load, an old
sadc
might still be running when cron starts a new one. Without locking,
this situation can result in a corrupted system activity file.
-V
Print version number then exit.
ENVIRONMENT
The
sadc
command takes into account the following environment variable:
S_TIME_DEF_TIME
If this variable exists and its value is
UTC
then
sadc
will save its data in UTC time.
sadc
will also use UTC time instead of local time to determine the current
daily data file located in the
/var/log/sa
directory.
EXAMPLES
/usr/lib/sa/sadc 1 10 /tmp/datafile
Write 10 records of one second intervals to the /tmp/datafile binary file.
BUGS
/proc
filesystem must be mounted for the
sadc
command to work.
All the statistics are not necessarily available, depending on the kernel version used.
FILES
/var/log/sa/sadd
Indicate the daily data file, where the
dd
parameter is a number representing the day of the month.
/proc
contains various files with system statistics.
