sysstat - sysstat configuration file.
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
- Number of days after which daily data files are to be
compressed. The compression program is given in the ZIP variable.
- 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
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
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.
- Set this variable to false to prevent the sa2 script
from generating reports (the sarDD files).
- Directory where the standard system activity daily data and
report files are saved. Its default value is /var/log/sysstat.
- 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.
- 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.
- Program used to compress data and report files.
Sebastien Godard (sysstat <at> orange.fr)