sadc(8) - man - phpMan

SADC(8)                                  Linux User's Manual                                 SADC(8)



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  in‐
       terval  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 ex‐
       plicitly 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 sys‐
       tem 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 cur‐
              rent one.

       -f     fdatasync() will be used to ensure data is written to disk. This differs from the nor‐
              mal  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 truncat‐
              ing it. Failure to get the lock is fatal, except in the case of trying to write a nor‐
              mal (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)


SEE ALSO
       sar(1), sa1(8), sa2(8), sadf(1), sysstat(5)

       https://github.com/sysstat/sysstat
       http://pagesperso-orange.fr/sebastien.godard/



Linux                                         JULY 2020                                      SADC(8)