=head1 NAME

rrdtool graph - Round Robin Database tool grapher functions

WARNING: This is for version 1.1.x which is B<I<BETA>> software.
The software may contain serious bugs. Some of the items
described in here may not yet exist (although this should
be mentioned) or still be in the alpha stage.  As with every
other RRDtool release: use at your own risk.  In contrast with
the stable version of RRDtool, this release may contain bugs
known to the authors.  It is highly recommended that you subscribe
to the mailing list.

=head1 SYNOPSYS

B<rrdtool graph /home/httpd/html/test.png --img-format PNG \>

followed by any of the examples below

=head1 DESCRIPTION

For your convenience some of the commands are explained here
by using detailed examples. They are not always cut-and-paste
ready because comments are intermixed with the examples.

=head1 EXAMPLES

=head2 Nicely formatted legend section

    DEF:ds0=/home/rrdtool/data/router1.rrd:ds0:AVERAGE
    DEF:ds1=/home/rrdtool/data/router1.rrd:ds1:AVERAGE
    VDEF:ds0max=ds0,MAXIMUM,8,*
    VDEF:ds0avg=ds0,AVERAGE,8,*
    VDEF:ds0min=ds0,MINIMUM,8,*
    VDEF:ds0pct=95,ds0,PERCENTILE,8,*
    VDEF:ds1max=ds1,MAXIMUM,8,*
    VDEF:ds1avg=ds1,AVERAGE,8,*
    VDEF:ds1min=ds1,MINIMUM,8,*
    VDEF:ds1pct=95,ds1,PERCENTILE,8,*
Note: consolidation occurs here.
    CDEF:ds0bits=ds0,8,*
    CDEF:ds1bits=ds1,8,*
Note: 10 spaces to move text to the right
    COMMENT:"          "
Note: three times size == 11 chars, "###.## xBps"
    COMMENT:"Maximum    "
    COMMENT:"Average    "
    COMMENT:"Minimum    "
Note: last line contains new-line character
    COMMENT:"95th percentile\n"
    AREA:ds0bits#00C000:"Inbound "
    GPRINT:ds0max:"%6.2lf %Sbps"
    GPRINT:ds0avg:"%6.2lf %Sbps"
    GPRINT:ds0min:"%6.2lf %Sbps"
    GPRINT:ds0pct:"%6.2lf %Sbps\n"
    LINE1:ds1bits#0000FF:"Outbound"
    GPRINT:ds1max:"%6.2lf %Sbps"
    GPRINT:ds1avg:"%6.2lf %Sbps"
    GPRINT:ds1min:"%6.2lf %Sbps"
    GPRINT:ds1pct:"%6.2lf %Sbps\n"

=head2 Offsetting a line on the y-axis

Depending on your needs you can do this in two ways:

=over 4

=item *

Offset the data, then graph this

    DEF:mydata=my.rrd:ds:AVERAGE
Note: this will also influence anything that uses "data"
    CDEF:data=mydata,100,+
    LINE1:data#FF0000:"Data with offset"

=item *

Graph the original data, with an offset

    DEF:mydata=my.rrd:ds:AVERAGE
Note: no color in the first line so it is not visible
    LINE1:100
Note: the second line gets stacked on top of the first one
    LINE1:data#FF0000:"Data with offset":STACK

=back

=head2 Time ranges

    Last four weeks: --start end-4w --end 00:00
    Januari 2001:    --start 200101010000 --end start+31d
    Januari 2001:    --start 200101010000 --end 200102010000
    Last hour:       --start end-1h
    Last 24 hours:   <nothing at all>
    Yesterday:       --end 00:00

=head2 Viewing Januari+Februari 2000 and 2001 together

Define a graph area of 31+29 days (!) spanning Jan. and Feb.
    --start 20000101 --end 20000301
    DEF:jan2000=router.rrd:ds0:AVERAGE:start 20000101 end start+31d
    DEF:jan2001=router.rrd:ds0:AVERAGE:start 20010101 end start+31d
Note: mind the extra day in 2000 ...
    DEF:feb2000=router.rrd:ds0:AVERAGE:start 20000201 end start+29d
Note: 29 feb 2001 is *unknown*
    DEF:feb2001=router.rrd:ds0:AVERAGE:start 20010201 end start+28d
    VDEF:offset=jan2001,FIRST,jan2000,FIRST,-,-1,*
    [ more of the usual VDEF and CDEF stuff if you like ]
    LINE1:jan2000#00003F:"Januari 2000"
    [ gprint stuff ]
    LINE1:feb2001#003F00:"Februari 2000"
    [ gprint stuff ]
Note: offset is made negative by the VDEF statement
    SHIFT:offset
    LINE1:jan2001#0000FF:"Januari 2001"
    [ gprint stuff ]
    LINE1:feb2001#00FF00:"Februari 2001"
    [ gprint stuff ]

=head1 SEE ALSO

L<rrdgraph> gives an overview of how B<rrdtool graph> works.
L<rrdgraph_data> describes B<DEF>,B<CDEF> and B<VDEF> in detail,
L<rrdgraph_rpn> describes the B<RPN> language used in the B<?DEF> statements,
L<rrdgraph_graph> page describes all of the graph and print functions.

Make sure to read L<rrdgraph_examples> for tipsE<amp>tricks.

=head1 AUTHOR

Program by Tobias Oetiker E<lt>oetiker@ee.ethz.chE<gt>

This manual page by Alex van den Bogaerdt E<lt>alex@ergens.op.het.netE<gt>