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 compressed.  The compression program is given in the ZIP variable.

   DELAY_RANGE
          Tell sa2 script to wait for a random delay in the indicated range before running.  This delay is expressed in seconds, and is aimed at preventing a massive  I/O  burst  at  the
          same time on VM sharing the same storage area.  A value of 0 means that sa2 script will generate its reports files immediately.

   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 saYYYYM‐
          MDD 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  be‐
          fore  midnight  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/sa directory during the majority of a given day.

   REPEAT_HEADER
          Maximum number of lines after which a header will be inserted in the report generated by sa2 script. By default there is only a header at the beginning of each report and it is
          not repeated afterwards.

   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.

   UMASK  The sa1 and sa2 scripts generate system activity data and report files in the /var/log/sa directory. By default the files are created with umask 0022 and are therefore readable
          for all users. Change this variable to restrict the permissions on the files (e.g. use 0027 to adhere to more strict security standards).

   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.

FILE

   /etc/sysstat/sysstat

AUTHOR

   Sebastien Godard (sysstat <at> orange.fr)

SEE ALSO

   sadc(8), sa1(8), sa2(8)

   https://github.com/sysstat/sysstat
   https://sysstat.github.io/

Linux AUGUST 2023 SYSSTAT(5)