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 compressed.  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 directory 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 using 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
              fractional  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" command 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 generating reports (the sarDD files).

       SA_DIR Directory  where  the  standard system activity daily data and report 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 ignored 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)

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