sadc

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 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  explic-
       itly passed to sadc to be collected (see option -S below).

       The  standard  system activity daily data file is named saDD unless op-
       tion -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  direc-
       tory.  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  con-
       sidered  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  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/lib/sysstat/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.

       -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  ex-
              ists and has a format unknown to sadc then it will be truncated.
              This may be useful for daily data files created by an older ver-
              sion  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 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  writ-
              ten 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  fa-
              tal,  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 { 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 in-
              dicates  that  IPv6 statistics should be collected by sadc.  The
              POWER keyword indicates that sadc should collect  power  manage-
              ment  statistics.   The SNMP keyword indicates that SNMP statis-
              tics 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  exten-
              sions) 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 ker-
       nel  version used.  sadc assumes that you are using at least a 2.6 ker-
       nel.

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                            FEBRUARY 2019                         SADC(8)