RRDGRAPH_DATA(1)             rrdtool             RRDGRAPH_DATA(1)



NNAAMMEE
       rrdgraph_data - preparing data for graphing in rrdtool
       graph

SSYYNNOOPPSSIISS
       DDEEFF::_<_v_n_a_m_e_>=_<_r_r_d_f_i_l_e_>:_<_d_s_-
       _n_a_m_e_>:_<_C_F_>[:step=_<_s_t_e_p_>][:start=_<_t_i_m_e_>][:end=_<_t_i_m_e_>][:reduce=_<_CC_FF_>]

       VVDDEEFF:_v_n_a_m_e=_R_P_N _e_x_p_r_e_s_s_i_o_n

       CCDDEEFF:_v_n_a_m_e=_R_P_N _e_x_p_r_e_s_s_i_o_n

DDEESSCCRRIIPPTTIIOONN
       These three instructions extract data values out of the
       RRRRDD files, optionally altering them (think, for example,
       of a bytes to bits conversion). If so desired, you can
       also define variables containing useful information such
       as maximum, minimum etcetera. Two of the instructions use
       a language called RRPPNN which is described in its own manual
       page.

       Variable names (_v_n_a_m_e) must be made up strings of the fol-
       lowing characters "A-Z, a-z, 0-9, -,_" and a maximum
       length of 255 characters.

       When picking variable names, make sure you do not choose a
       name that is already taken by an RPN operator. A save bet
       it to use lowercase or mixedcase names for variables since
       operators will always be in uppercase.

DDEEFF
       DDEEFF::_<_v_n_a_m_e_>=_<_r_r_d_f_i_l_e_>:_<_d_s_-
       _n_a_m_e_>:_<_C_F_>[:step=_<_s_t_e_p_>][:start=_<_t_i_m_e_>][:end=_<_t_i_m_e_>][:reduce=_<_CC_FF_>]

       This command fetches data from an RRRRDD file.  The virtual
       name _v_n_a_m_e can then be used throughout the rest of the
       script. By default, an RRRRAA which contains the correct con-
       solidated data at an appropriate resolution will be cho-
       sen.  The resolution can be overridden with the --step
       option.  The resolution can again be overridden by speci-
       fying the sstteepp ssiizzee.  The time span of this data is the
       same as for the graph by default, you can override this by
       specifying ssttaarrtt aanndd eenndd.  Remember to escape colons in
       the time specification!

       If the resolution of the data is higher than the resolu-
       tion of the graph, the data will be further consolidated.
       This may result in a graph that spans slightly more time
       than requested.  Ideally each point in the graph should
       correspond with one CCDDPP from an RRRRAA.  For instance, if
       your RRRRDD has an RRRRAA with a resolution of 1800 seconds per
       CCDDPP, you should create an image with width 400 and time
       span 400*1800 seconds (use appropriate start and end
       times, such as "--start end-8days8hours").

       If consolidation needs to be done, the CCFF of the RRRRAA spec-
       ified in the DDEEFF itself will be used to reduce the data
       density. This behaviour can be changed using
       ":reduce=<CF>".  This optional parameter specifies the CCFF
       to use during the data reduction phase.

       Example:

               DEF:ds0=router.rrd:ds0:AVERAGE
               DEF:ds0weekly=router.rrd:ds0:AVERAGE:step=7200
               DEF:ds0weekly=router.rrd:ds0:AVERAGE:start=end-1h
               DEF:ds0weekly=router.rrd:ds0:AVERAGE:start=11\:00:end=start+1h

VVDDEEFF
       VVDDEEFF:_v_n_a_m_e=_R_P_N _e_x_p_r_e_s_s_i_o_n

       This command returns a value and/or a time according to
       the RRPPNN statements used. The resulting _v_n_a_m_e will, depend-
       ing on the functions used, have a value and a time compo-
       nent.  When you use this _v_n_a_m_e in another RRPPNN expression,
       you are effectively inserting its value just as if you had
       put a number at that place.  The variable can also be used
       in the various graph and print elements.

       Example: "VDEF:avg=mydata,AVERAGE"

       Note that currently only agregation functions work in VDEF
       rpn expressions.  Patches to change this are welcome.

CCDDEEFF
       CCDDEEFF:_v_n_a_m_e=_R_P_N _e_x_p_r_e_s_s_i_o_n

       This command creates a new set of data points (in memory
       only, not in the RRRRDD file) out of one or more other data
       series. The RRPPNN instructions are used to evaluate a mathe-
       matical function on each data point. The resulting _v_n_a_m_e
       can then be used further on in the script, just as if it
       were generated by a DDEEFF instruction.

       Example: "CDEF:mydatabits=mydata,8,*"

SSEEEE AALLSSOO
       rrdgraph gives an overview of how rrrrddttooooll ggrraapphh works.
       rrdgraph_data describes DDEEFF,CCDDEEFF and VVDDEEFF in detail.  rrd-
       graph_rpn describes the RRPPNN language used in the ??DDEEFF
       statements.  rrdgraph_graph page describes all of the
       graph and print functions.

       Make sure to read rrdgraph_examples for tips&tricks.

AAUUTTHHOORR
       Program by Tobias Oetiker <tobi@oetiker.ch>

       This manual page by Alex van den Bogaerdt
       <alex@ergens.op.het.net>



1.2.15                      2006-07-14           RRDGRAPH_DATA(1)
