SADC(8) Linux User's Manual SADC(8)NAMEsadc - System activity data collector.
SYNOPSIS
/usr/lib64/sa/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/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 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 end‐
lessly. 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 exam‐
ple, one of the system startup script may write the restart mark to the
daily data file by the command entry:
/usr/lib64/sa/sadc -
The sadc command is intended to be used as a backend to the sar com‐
mand.
Note: The sadc command only reports on local activities.
OPTIONS-C comment
When neither the interval nor the count parameters are speci‐
fied, this option tells sadc to write a dummy record containing
the specified comment string. This comment can then be dis‐
played with option -C of sar.
-F The creation of outfile will be forced. If the file already
exists and has a format unknown to sadc then it will be trun‐
cated. 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.
-Lsadc 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 lock‐
ing, 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 key‐
word 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 addi‐
tion 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 there‐
fore 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/sa directory.
EXAMPLES
/usr/lib64/sa/sadc 1 10 /tmp/datafile
Write 10 records of one second intervals to the /tmp/datafile
binary file.
/usr/lib64/sa/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 ker‐
nel version used. sadc assumes that you are using at least a 2.6 ker‐
nel.
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.
AUTHOR
Sebastien Godard (sysstat <at> orange.fr)
SEE ALSOsar(1), sa1(8), sa2(8), sadf(1), sysstat(5)
http://pagesperso-orange.fr/sebastien.godard/
Linux SEPTEMBER 2010 SADC(8)
