sysstat

SYSSTAT(5)                    Linux User's Manual                   SYSSTAT(5)

NAME
       sysstat - sysstat configuration file.

DESCRIPTION
       This file is read by sa1(8) and sa2(8) shell scripts from the sysstat's
       set of tools.  It consists of a sequence of shell variable  assignments
       used  to  configure  sysstat logging.  The variables and their meanings
       are:

       COMPRESSAFTER
              Number of days after which daily  data  files  are  to  be  com-
              pressed.  The compression program is given in the ZIP variable.

       HISTORY
              The  number  of  days during which a daily data file or a report
              should be kept. Data files or reports older than this number  of
              days will be removed by the sa2(8) shell script.  Data files and
              reports are normally saved in  the  /var/log/sysstat  directory,
              under  the  name  saDD  (for data files) or sarDD (for reports),
              where the DD parameter indicates the current day.

              The number of files actually kept in the /var/log/sysstat direc-
              tory  may  be  slightly higher than the HISTORY value due to the
              way the sa2 script figures out which files  are  to  be  removed
              (see below "How the sa2(8) script applies HISTORY value"). Using
              a value of 28 keeps a whole month's worth of data.  If  you  set
              HISTORY  to a value greater than 28 then you should consider us-
              ing sadc's option -D to prevent  older  data  files  from  being
              overwritten  (see sadc(8) manual page). In this latter case data
              files are named saYYYYMMDD and reports sarYYYYMMDD,  where  YYYY
              stands for the current year, MM for the current month and DD for
              the current day.

              How the sa2(8) script applies HISTORY value

              The sa2 script uses the "find" command with the "-mtime"  option
              to  figure out which files are to be removed. The "find" command
              interprets this value as "N 24 hour periods", ignoring any frac-
              tional  part.  This means that the last modified time of a given
              sa[r]DD data or report file, using a HISTORY of 1, has  to  have
              been  modified  at least two days ago before it will be removed.
              And for a HISTORY of 28 that would mean 29 days ago.

              To figure out how a HISTORY of 28 is  applied  in  practice,  we
              need to consider that the sa2 script that issues the "find" com-
              mand  to  remove  the  old  files  typically  runs  just  before
              mid-night  on  a  given  system, and since the first record from
              sadc can also  be  written  to  the  previous  day's  data  file
              (thereby  moving its modification time up a bit), the sa2 script
              will leave 30 files untouched. So  for  a  setting  of  28,  and
              counting  the data file of the current day, there will always be
              31 files (or 30 files, depending on the  number  of  days  in  a
              month)  in the /var/log/sysstat directory during the majority of
              a given day.  E.g.:

              April 30th: 31 files (Apr 30th-1st, Mar 31th)
              May 1st: 30 files (May 1st, Apr 30th-2nd)

              Yet we can note the following exceptions (as inspected  at  Noon
              of the given day):

              February 28th: 31 files (Feb 28th-1st, Jan 31st, 30th & 29th)
              March 1st: 30 files (Mar 1st, Feb 28th-2nd, Jan 31st & 30th)
              March 2nd: 29 files (Mar 1st & 2nd, Feb 28th-3rd, Jan. 31st)
              March 3rd: 28 files (Mar 1st-3rd, Feb 28th-4th)
              March 4th - March 28th: 28 files
              March 29th: 29 files
              March 30th: 30 files
              March 31st: 31 files

              (Determining the number of files in March on a leap year is left
              as an exercise for the reader).

              Things are simpler if you use  the  sa[r]YYYYMMDD  name  format.
              Apply  the  same  logic  as above in this case and you will find
              that there are always HISTORY + 3 files in the  /var/log/sysstat
              directory during the majority of a given day.

       REPORTS
              Set this variable to false to prevent the sa2 script from gener-
              ating reports (the sarDD files).

       SA_DIR Directory where the standard system activity daily data and  re-
              port files are saved. Its default value is /var/log/sysstat.

       SADC_OPTIONS
              Options  that  should  be passed to sadc(8).  With these options
              (see sadc(8) manual page), you can select some  additional  data
              which  are going to be saved in daily data files.  These options
              are used only when a new data file is created. They will be  ig-
              nored with an already existing one.

       YESTERDAY
              By  default  sa2 script generates yesterday's summary, since the
              cron job usually runs right after midnight. If you want  sa2  to
              generate  the summary of the same day (for example when cron job
              runs at 23:53) set this variable to no.

       ZIP    Program used to compress data and report files.

FILES
       /etc/sysstat/sysstat

AUTHOR
       Sebastien Godard (sysstat <at> orange.fr)

SEE ALSO
       sadc(8), sa1(8), sa2(8)

       https://github.com/sysstat/sysstat

       http://pagesperso-orange.fr/sebastien.godard/

Linux                              JULY 2018                        SYSSTAT(5)