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Man page of SADC
SADC
Section: Linux User's Manual (8)
Updated: MARCH 2009
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NAME
sadc - System activity data collector.
SYNOPSIS
/usr/lib/sysstat/sadc [ -C
comment
] [ -S { INT | DISK | SNMP | IPV6 | POWER | XDISK | ALL | XALL } ] [ -F ] [ -L ] [ -V ] [
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, the
/var/log/sysstat/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 disk 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, 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.
- -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 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 partition 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.
- -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.
FILES
/var/log/sysstat/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.
AUTHOR
Sebastien Godard (sysstat <at> orange.fr)
SEE ALSO
sar(1),
sa1(8),
sa2(8),
sadf(1),
isag(1)
http://pagesperso-orange.fr/sebastien.godard/
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- OPTIONS
-
- ENVIRONMENT
-
- EXAMPLES
-
- BUGS
-
- FILES
-
- AUTHOR
-
- SEE ALSO
-
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