RRDGRAPH_DATA(1) rrdtool RRDGRAPH_DATA(1) NNAAMMEE rrdgraph_data - preparing data for graphing in rrdtool graph SSYYNNOOPPSSIISS DDEEFF::_<_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=_<_CC_FF_>] VVDDEEFF:_v_n_a_m_e=_R_P_N _e_x_p_r_e_s_s_i_o_n CCDDEEFF:_v_n_a_m_e=_R_P_N _e_x_p_r_e_s_s_i_o_n DDEESSCCRRIIPPTTIIOONN These three instructions extract data values out of the RRRRDD 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 RRPPNN which is described in its own manual page. Variable names (_v_n_a_m_e) must be made up strings of the following 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 safe bet it to use lowercase or mixed case names for variables since operators will always be in uppercase. DDEEFF DDEEFF::_<_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=_<_CC_FF_>] This command fetches data from an RRRRDD file. The virtual name _v_n_a_m_e can then be used throughout the rest of the script. By default, an RRRRAA which contains the correct consolidated data at an appropriate resolution will be chosen. The resolution can be overridden with the --step option. The resolution can again be overridden by specifying the sstteepp ssiizzee. The time span of this data is the same as for the graph by default, you can override this by specifying ssttaarrtt aanndd eenndd. Remember to escape colons in the time specification! If the resolution of the data is higher than the resolution 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 CCDDPP from an RRRRAA. For instance, if your RRRRDD has an RRRRAA with a resolution of 1800 seconds per CCDDPP, 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 CCFF of the RRRRAA specified in the DDEEFF itself will be used to reduce the data density. This behavior can be changed using ":reduce=__". This optional parameter specifies the CCFF 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 VVDDEEFF VVDDEEFF:_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 RRPPNN statements used. The resulting _v_n_a_m_e will, depending on the functions used, have a value and a time component. When you use this _v_n_a_m_e in another RRPPNN 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 aggregation functions work in VDEF rpn expressions. Patches to change this are welcome. CCDDEEFF CCDDEEFF:_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 RRRRDD file) out of one or more other data series. The RRPPNN instructions are used to evaluate a mathematical 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 DDEEFF instruction. Example: "CDEF:mydatabits=mydata,8,*" AAbboouutt CCDDEEFF vveerrssuuss VVDDEEFF At some point in processing, RRRRDDttooooll has gathered an array of rates ready to display. CCDDEEFF works on such an array. For example, _C_D_E_F_:_n_e_w_=_d_s_0_,_8_,_* would multiply each of the array members by eight (probably transforming bytes into bits). The result is an array containing the new values. VVDDEEFF also works on such an array but in a different way. For example, _V_D_E_F_:_m_a_x_=_d_s_0_,_M_A_X_I_M_U_M would scan each of the array members and store the maximum value. WWhheenn ddoo yyoouu uussee VVDDEEFF vveerrssuuss CCDDEEFF?? Use CCDDEEFF to transform your data prior to graphing. In the above example, we'd use a CCDDEEFF to transform bytes to bits before graphing the bits. You use a VVDDEEFF if you want _m_a_x_(_1_,_5_,_3_,_2_,_4_) to return five which would be displayed in the graph's legend (to answer, what was the maximum value during the graph period). If you want to apply 'complex' operations to the result of a VDEF you have to use a CDEF again since VDEFs only look like RPN expressions, they aren't really. SSEEEE AALLSSOO rrdgraph gives an overview of how rrrrddttooooll ggrraapphh works. rrdgraph_data describes DDEEFF,CCDDEEFF and VVDDEEFF in detail. rrdgraph_rpn describes the RRPPNN language used in the ??DDEEFF statements. rrdgraph_graph page describes all of the graph and print functions. Make sure to read rrdgraph_examples for tips&tricks. AAUUTTHHOORR Program by Tobias Oetiker This manual page by Alex van den Bogaerdt with corrections and/or additions by several people 1.4.8 2013-05-23 RRDGRAPH_DATA(1)