Ubuntu Manpage: sadc - System activity data collector.

NAME

       sadc - System activity data collector.

SYNOPSIS

       /usr/lib/sysstat/sadc [ -C comment ] [ -D ] [ -F ] [ -f ] [ -L ] [ -V ] [ -S { keyword[,...] | ALL | XALL
       } ] [ interval [ count ] ] [ outfile ]

DESCRIPTION

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 standard output. If
outfile is set to -, then sadc uses the standard system activity daily data file (see below). In this
case, if the file already exists, sadc will overwrite it if it is from a previous month. By default sadc
collects most of the data available from the kernel. But there are also optional metrics, for which the
relevant options must be explicitly passed to sadc to be collected (see option -S below).

The standard system activity daily data file is named saDD unless option -D is used, in which case its
name is saYYYYMMDD, where YYYY stands for the current year, MM for the current month and DD for the
current day. By default it is located in the /var/log/sysstat directory. Yet it is possible to specify an
alternate location for it: If outfile is a directory (instead of a plain file) then it will be considered
as the directory where the standard system activity daily data file will be saved.

When the count parameter is not specified, sadc writes its data endlessly. When both interval and count
are not specified, and option -C is not used, 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/sysstat/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

-C comment
When neither the interval nor the count parameters are specified, this option tells sadc to write
a dummy record containing the specified comment string. This comment can then be displayed with
option -C of sar.

-D Use saYYYYMMDD instead of saDD as the standard system activity daily data file name.

-F The creation of outfile will be forced. If the file already exists and has a format unknown to
sadc then it will be truncated. This may be useful for daily data files created by an older
version of sadc and whose format is no longer compatible with current one.

-f fdatasync() will be used to ensure data is written to disk. This differs from the normal operation
in that a sudden system reset is less likely to result in the saDD datafiles being corrupted.
However, this is at the expense of performance within the sadc process as forward progress will be
blocked while data is written to underlying disk instead of just to cache.

-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.

-S { keyword[,...] | ALL | XALL }
Possible keywords are DISK, INT, IPV6, POWER, SNMP, XDISK, ALL and XALL.
Specify which optional activities should be collected by sadc. Some activities are optional to
prevent data files from growing too large. The DISK keyword indicates that sadc should collect
data for block devices. The INT keyword indicates that sadc should collect data for system
interrupts. The IPV6 keyword indicates that IPv6 statistics should be collected by sadc. The POWER
keyword indicates that sadc should collect power management statistics. The SNMP keyword indicates
that SNMP statistics should be collected by sadc. The ALL keyword is equivalent to specifying all
the keywords above and therefore all previous activities are collected.

The XDISK keyword is an extension to the DISK one and indicates that partitions and filesystems
statistics should be collected by sadc in addition to disk statistics. This option works only with
kernels 2.6.25 and later. The XALL keyword is equivalent to specifying all the keywords above
(including keyword extensions) and therefore all possible activities are collected.

Important note: The activities (including optional ones) saved in an existing data file prevail
over those selected with option -S. As a consequence, appending data to an existing data file
will result in option -S being ignored.

-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/sysstat directory.

EXAMPLES

       /usr/lib/sysstat/sadc 1 10 /tmp/datafile
              Write 10 records of one second intervals to the /tmp/datafile binary file.

       /usr/lib/sysstat/sadc -C "Backup Start" /tmp/datafile
              Insert the comment "Backup Start" into the file /tmp/datafile.

BUGS

       The /proc filesystem must be mounted for the sadc command to work.

       All  the  statistics  are  not necessarily available, depending on the kernel version used.  sadc assumes
       that you are using at least a 2.6 kernel.

FILES

       /var/log/sysstat/saDD
       /var/log/sysstat/saYYYYMMDD
              The standard system activity daily data files and their default location.   YYYY  stands  for  the
              current year, MM for the current month and DD for the current day.
       /proc and /sys contain various files with system statistics.

AUTHOR

       Sebastien Godard (sysstat <at> orange.fr)