# phpman > man > Log::Log4perl::Appender::RRDs(3pm)

## NAME
    [Log::Log4perl::Appender::RRDs](https://www.chedong.com/phpMan.php/perldoc/Log%3A%3ALog4perl%3A%3AAppender%3A%3ARRDs/markdown) - Log to a RRDtool Archive

## SYNOPSIS
        use [Log::Log4perl](https://www.chedong.com/phpMan.php/perldoc/Log%3A%3ALog4perl/markdown) qw(get_logger);
        use RRDs;

        my $DB = "myrrddb.dat";

        [RRDs::create](https://www.chedong.com/phpMan.php/perldoc/RRDs%3A%3Acreate/markdown)(
          $DB, "--step=1",
          "DS:myvalue:GAUGE:2:U:U",
          "RRA:MAX:0.5:1:120");

        print time(), "\n";

        [Log::Log4perl](https://www.chedong.com/phpMan.php/perldoc/Log%3A%3ALog4perl/markdown)->init(\qq{
          log4perl.category = INFO, RRDapp
          log4perl.appender.RRDapp = [Log::Log4perl::Appender::RRDs](https://www.chedong.com/phpMan.php/perldoc/Log%3A%3ALog4perl%3A%3AAppender%3A%3ARRDs/markdown)
          log4perl.appender.RRDapp.dbname = $DB
          log4perl.appender.RRDapp.layout = [Log::Log4perl::Layout::PatternLayout](https://www.chedong.com/phpMan.php/perldoc/Log%3A%3ALog4perl%3A%3ALayout%3A%3APatternLayout/markdown)
          log4perl.appender.RRDapp.layout.ConversionPattern = N:%m
        });

        my $logger = get_logger();

        for(10, 15, 20, 25) {
            $logger->info($_);
            sleep 1;
        }

## DESCRIPTION
    "[Log::Log4perl::Appender::RRDs](https://www.chedong.com/phpMan.php/perldoc/Log%3A%3ALog4perl%3A%3AAppender%3A%3ARRDs/markdown)" appenders facilitate writing data to RRDtool round-robin
    archives via Log4perl. For documentation on RRD and its Perl interface "RRDs" (which comes with
    the distribution), check out <<http://rrdtool.org>>.

    Messages sent to Log4perl's RRDs appender are expected to be numerical values (ints or floats),
    which then are used to run a "rrdtool update" command on an existing round-robin database. The
    name of this database needs to be set in the appender's "dbname" configuration parameter.

    If there's more parameters you wish to pass to the "update" method, use the "rrdupd_params"
    configuration parameter:

        log4perl.appender.RRDapp.rrdupd_params = --template=in:out

    To read out the round robin database later on, use "rrdtool fetch" or "rrdtool graph" for
    graphic displays.

## LICENSE
    Copyright 2002-2013 by Mike Schilli <<m@perlmeister.com>> and Kevin Goess <<cpan@goess.org>>.

    This library is free software; you can redistribute it and/or modify it under the same terms as
    Perl itself.

## AUTHOR
    Please contribute patches to the project on Github:

        <http://github.com/mschilli/log4perl>

    Send bug reports or requests for enhancements to the authors via our

    MAILING LIST (questions, bug reports, suggestions/patches): <log4perl-devel@lists.sourceforge.net>

    Authors (please contact them via the list above, not directly): Mike Schilli
    <<m@perlmeister.com>>, Kevin Goess <<cpan@goess.org>>

    Contributors (in alphabetical order): Ateeq Altaf, Cory Bennett, Jens Berthold, Jeremy Bopp,
    Hutton Davidson, Chris R. Donnelly, Matisse Enzer, Hugh Esco, Anthony Foiani, James FitzGibbon,
    Carl Franks, Dennis Gregorovic, Andy Grundman, Paul Harrington, Alexander Hartmaier David Hull,
    Robert Jacobson, Jason Kohles, Jeff Macdonald, Markus Peter, Brett Rann, Peter Rabbitson, Erik
    Selberg, Aaron Straup Cope, Lars Thegler, David Viner, Mac Yang.