1SYSSTAT(5) Linux User's Manual SYSSTAT(5)
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6 sysstat - sysstat configuration file.
7
9 This file is read by sa1(8) and sa2(8) shell scripts from the sysstat's
10 set of tools. It consists of a sequence of shell variable assignments
11 used to configure sysstat logging. The variables and their meanings
12 are:
13 COMPRESSAFTER
15 Number of days after which daily data files are to be com‐
16 pressed. The compression program is given in the ZIP variable.
17 HISTORY
20 The number of days during which a daily data file or a report
21 should be kept. Data files or reports older than this number of
22 days will be removed by the sa2(8) shell script. Data files and
23 reports are normally saved in the /var/log/sa directory, under
24 the name saDD (for data files) or sarDD (for reports), where the
25 DD parameter indicates the current day.
26 The number of files actually kept in the /var/log/sa directory
28 may be slightly higher than the HISTORY value due to the way the
29 sa2 script figures out which files are to be removed (see below
30 "How the sa2(8) script applies HISTORY value"). Using a value of
31 28 keeps a whole month's worth of data.
32 How the sa2(8) script applies HISTORY value
34 The sa2 script uses the "find" command with the "-mtime" option
36 to figure out which files are to be removed. The "find" command
37 interprets this value as "N 24 hour periods", ignoring any frac‐
38 tional part. This means that the last modified time of a given
39 sa[r]DD data or report file, using a HISTORY of 1, has to have
40 been modified at least two days ago before it will be removed.
41 And for a HISTORY of 28 that would mean 29 days ago.
42 To figure out how a HISTORY of 28 is applied in practice, we
44 need to consider that the sa2 script that issues the "find" com‐
45 mand to remove the old files typically runs just before mid-
46 night on a given system, and since the first record from sadc
47 can also be written to the previous day's data file (thereby
48 moving its modification time up a bit), the sa2 script will
49 leave 30 files untouched. So for a setting of 28, and counting
50 the data file of the current day, there will always be 31 files
51 (or 30 files, depending on the number of days in a month) in the
52 /var/log/sa directory during the majority of a given day. E.g.:
53 April 30th: 31 files (Apr 30th-1st, Mar 31th)
55 May 1st: 30 files (May 1st, Apr 30th-2nd)
56 Yet we can note the following exceptions (as inspected at Noon
58 of the given day):
59 February 28th: 31 files (Feb 28th-1st, Jan 31st, 30th & 29th)
61 March 1st: 30 files (Mar 1st, Feb 28th-2nd, Jan 31st & 30th)
62 March 2nd: 29 files (Mar 1st & 2nd, Feb 28th-3rd, Jan. 31st)
63 March 3rd: 28 files (Mar 1st-3rd, Feb 28th-4th)
64 March 4th - March 28th: 28 files
65 March 29th: 29 files
66 March 30th: 30 files
67 March 31st: 31 files
68 (Determining the number of files in March on a leap year is left
70 as an exercise for the reader).
71 SADC_OPTIONS
74 Options that should be passed to sadc(8). With these options
75 (see sadc(8) manual page), you can select some additional data
76 which are going to be saved in daily data files. These options
77 are used only when a new data file is created. They will be
78 ignored with an already existing one.
79 ZIP Program used to compress data and report files.
82
85 /etc/sysconfig/sysstat
86
89 Sebastien Godard (sysstat <at> orange.fr)
90
92 sadc(8), sa1(8), sa2(8)
93 http://pagesperso-orange.fr/sebastien.godard/
95Linux SEPTEMBER 2010 SYSSTAT(5)