sadc(8)
NAME
sadc - System activity data collector.
SYNOPSIS
/usr/lib/sysstat/sadc [ -C comment ] [ -D ] [ -F ] [ -L ] [ -V ] [ -S {
INT | DISK | SNMP | IPV6 | POWER | XDISK | 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.
-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 { INT | DISK | SNMP | IPV6 | POWER | XDISK | ALL | XALL [,...] }
Specify which optional activities should be collected by sadc.
Some activities are optional to prevent data files from growing
too large. The INT keyword indicates that sadc should collect
data for system interrupts. The DISK keyword indicates that
sadc should collect data for block devices. The SNMP and IPV6
keywords indicate respectively that SNMP and IPv6 statistics
should be collected by sadc. The POWER keyword indicates that
sadc should collect power management statistics. 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)
SEE ALSO
sar(1), sa1(8), sa2(8), sadf(1), sysstat(5) http://pagesperso-orange.fr/sebastien.godard/
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