How do I rotate log files?

Posted on in Categories , , , , last updated April 2, 2008

Q. How do I rotate log files under Linux operating system?

A. You need use tool called logrotate, which is designed to ease administration of systems that generate large numbers of log files. It allows automatic rotation, compression, removal, and mailing of log files.

Each log file may be handled daily, weekly, monthly, or when it grows too large. With this tool you keep logs longer with less disk space.

Default configuration file

The default configuration file is /etc/logrotate.conf:
# see "man logrotate" for details
# rotate log files weekly
weekly
# keep 4 weeks worth of backlogs
rotate 4
# create new (empty) log files after rotating old ones
create
# uncomment this if you want your log files compressed
#compress
# RPM packages drop log rotation information into this directory
include /etc/logrotate.d
# no packages own wtmp -- we'll rotate them here
/var/log/wtmp {
monthly
create 0664 root utmp
rotate 1
}
Service or server specific configurations stored in /etc/logrotate.d directory, for example here is sample apache logrotate configuration file:# cat /etc/logrotate.d/httpdOutput:

/var/log/httpd/*.log {
 weekly
 rotate 52
 compress
  missingok
  notifempty
  sharedscripts
  postrotate
      /bin/kill -HUP `cat /var/run/httpd.pid 2>/dev/null` 2> /dev/null || true    endscript
}

Where,

  • weekly : Log files are rotated if the current weekday is less then the weekday of the last rotation or if more then a week has passed since the last rotation.
  • rotate 52 : Log files are rotated 52 times before being removed or mailed to the address specified in a mail directive. If count is 0, old versions are removed rather then rotated.
  • compress : Old versions of log files are compressed with gzip to save disk space.
  • missingok : If the log file is missing, go on to the next one without issuing an error message.
  • notifempty : Do not rotate the log if it is empty
  • sharedscripts : Normally, prerotate and postrotate scripts are run for each log which is rotated, meaning that a single script may be run multiple times for log file entries which match multiple files. If sharedscript is specified, the scripts are only run once, no matter how many logs match the wildcarded pattern. However, if none of the logs in the pattern require rotating, the scripts will not be run at all.
  • postrotate
    /bin/kill -HUP `cat /var/run/httpd.pid 2>/dev/null` 2> /dev/null || true
    endscript : The lines between postrotate and endscript (both of which must appear on lines by themselves) are executed after the log file is rotated. These directives may only appear inside a log file definition.

See complete working example: How to rotating logs with logrotate for Lighttpd web server.

Posted by: Vivek Gite

The author is the creator of nixCraft and a seasoned sysadmin and a trainer for the Linux operating system/Unix shell scripting. He has worked with global clients and in various industries, including IT, education, defense and space research, and the nonprofit sector. Follow him on Twitter, Facebook, Google+.

16 comment

  1. Am getting this problem very biggly

    Please help me out

    vi /etc/logrotate.conf
    # see “man logrotate” for details
    # rotate log files weekly
    weekly

    # keep 4 weeks worth of backlogs
    rotate 4

    # create new (empty) log files after rotating old ones
    create

    # uncomment this if you want your log files compressed
    #compress

    # RPM packages drop log rotation information into this directory
    include /etc/logrotate.d

    # no packages own wtmp — we’ll rotate them here
    /var/log/wtmp {
    monthly
    minsize 1M
    create 0664 root utmp
    rotate 1
    }

    cat /etc/logrotate.d/httpd

    /var/log/httpd/*log {
    missingok
    notifempty
    sharedscripts
    postrotate
    /sbin/service httpd reload > /dev/null 2>/dev/null || true
    endscript
    }

    My server is running nearly 10 sites and all those creating log files under statistics in vhosts.
    it wil become more than 30 gb with in week. how to control it. please reply me

    1. @Ela
      Its always a good idea to rotate logs according to size instead of age when the logs are too big or too small. Rotating logs according to age favours for moderate logs only.

  2. Dear friends,
    how can use this tool? it is downloadable tool??
    i need it but i can not find any thing, is it a feature in linux of a tool which can download it?
    would you please help me,
    it’s very helpful to me ,
    please

  3. Hello,

    I have an issue. I want to rotate log using compression. The thing is the filename:

    /path/sessionId{blabla}

    So I tried /path/* but doing that, every gz archive is compressed again into .gz.gz

    Any idea?

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