


rrdtool                                              RRDCREATE(1)



NNNNAAAAMMMMEEEE
     rrdtool create - Set up a new Round Robin Database

SSSSYYYYNNNNOOOOPPPPSSSSIIIISSSS
     rrrrrrrrddddttttoooooooollll ccccrrrreeeeaaaatttteeee _f_i_l_e_n_a_m_e [--------ssssttttaaaarrrrtttt|----bbbb _s_t_a_r_t _t_i_m_e]
     [--------sssstttteeeepppp|----ssss _s_t_e_p] [DDDDSSSS::::_d_s_-_n_a_m_e::::_D_S_T::::_h_e_a_r_t_b_e_a_t::::_m_i_n::::_m_a_x]
     [RRRRRRRRAAAA::::_C_F::::_x_f_f::::_s_t_e_p_s::::_r_o_w_s]

DDDDEEEESSSSCCCCRRRRIIIIPPPPTTTTIIIIOOOONNNN
     The create function of the RRDtool lets you set up new Round
     Robin Database (RRRRRRRRDDDD) files.  The file is created at its
     final, full size and filled with _*_U_N_K_N_O_W_N_* data.

     _f_i_l_e_n_a_m_e
             The name of the RRRRRRRRDDDD you want to create. RRRRRRRRDDDD files
             should end with the extension _._r_r_d. However, rrrrrrrrddddttttoooooooollll
             will accept any filename.

     --------ssssttttaaaarrrrtttt|----bbbb _s_t_a_r_t _t_i_m_e (default: now - 10s)
             Specifies the time in seconds since 1970-01-01 UTC
             when the first value should be added to the RRRRRRRRDDDD.
             rrrrrrrrddddttttoooooooollll will not accept any data timed before or at
             the time specified.

             See also AT-STYLE TIME SPECIFICATION section in the
             _r_r_d_f_e_t_c_h documentation for more ways to specify
             time.

     --------sssstttteeeepppp|----ssss _s_t_e_p (default: 300 seconds)
             Specifies the base interval in seconds with which
             data will be fed into the RRRRRRRRDDDD.

     DDDDSSSS::::_d_s_-_n_a_m_e::::_D_S_T::::_h_e_a_r_t_b_e_a_t::::_m_i_n::::_m_a_x
             A single RRRRRRRRDDDD can accept input from several data
             sources (DDDDSSSS).  (e.g. Incoming and Outgoing traffic
             on a specific communication line). With the DDDDSSSS
             configuration option you must define some basic
             properties of each data source you want to use to
             feed the RRRRRRRRDDDD.

             _d_s_-_n_a_m_e is the name you will use to reference this
             particular data source from an RRRRRRRRDDDD. A _d_s_-_n_a_m_e must
             be 1 to 19 characters long in the characters [a-zA-
             Z0-9_].

             _D_S_T defines the Data Source Type. See the section on
             "How to Measure" below for further insight.  The
             Datasource Type must be onw of the following:

             GGGGAAAAUUUUGGGGEEEE
                 is for things like temperatures or number of
                 people in a room or value of a RedHat share.



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rrdtool                                              RRDCREATE(1)



             CCCCOOOOUUUUNNNNTTTTEEEERRRR
                 is for continuous incrementing counters like the
                 InOctets counter in a router. The CCCCOOOOUUUUNNNNTTTTEEEERRRR data
                 source assumes that the counter never decreases,
                 except when a counter overflows.  The update
                 function takes the overflow into account.  The
                 counter is stored as a per-second rate. When the
                 counter overflows, RRDtool checks if the
                 overflow happened at the 32bit or 64bit border
                 and acts accordingly by adding an appropriate
                 value to the result.

             DDDDEEEERRRRIIIIVVVVEEEE
                 will store the derivative of the line going from
                 the last to the current value of the data
                 source. This can be useful for gauges, for
                 example, to measure the rate of people entering
                 or leaving a room. Internally, derive works
                 exaclty like COUNTER but without overflow
                 checks. So if your counter does not reset at 32
                 or 64 bit you might want to use DERIVE and
                 combine it with a MIN value of 0.

             AAAABBBBSSSSOOOOLLLLUUUUTTTTEEEE
                 is for counters which get reset upon reading.
                 This is used for fast counters which tend to
                 overflow. So instead of reading them normally
                 you reset them after every read to make sure you
                 have a maximal time available before the next
                 overflow. Another usage is for things you count
                 like number of messages since the last update.

             _h_e_a_r_t_b_e_a_t defines the maximum number of seconds that
             may pass between two updates of this data source
             before the value of the data source is assumed to be
             _*_U_N_K_N_O_W_N_*.

             _m_i_n and _m_a_x are optional entries defining the
             expected range of the data supplied by this data
             source. If _m_i_n and/or _m_a_x are defined, any value
             outside the defined range will be regarded as
             _*_U_N_K_N_O_W_N_*. If you do not know or care about min and
             max, set them to U for unknown. Note that min and
             max always refer to the processed values of the DS.
             For a traffic-CCCCOOOOUUUUNNNNTTTTEEEERRRR type DS this would be the max
             and min data-rate expected from the device.

             _I_f _i_n_f_o_r_m_a_t_i_o_n _o_n _m_i_n_i_m_a_l_/_m_a_x_i_m_a_l _e_x_p_e_c_t_e_d _v_a_l_u_e_s _i_s
             _a_v_a_i_l_a_b_l_e_, _a_l_w_a_y_s _s_e_t _t_h_e _m_i_n _a_n_d_/_o_r _m_a_x _p_r_o_p_e_r_t_i_e_s_.
             _T_h_i_s _w_i_l_l _h_e_l_p _R_R_D_t_o_o_l _i_n _d_o_i_n_g _a _s_i_m_p_l_e _s_a_n_i_t_y
             _c_h_e_c_k _o_n _t_h_e _d_a_t_a _s_u_p_p_l_i_e_d _w_h_e_n _r_u_n_n_i_n_g _u_p_d_a_t_e_.




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rrdtool                                              RRDCREATE(1)



     RRRRRRRRAAAA::::_C_F::::_x_f_f::::_s_t_e_p_s::::_r_o_w_s
             The purpose of an RRRRRRRRDDDD is to store data in the round
             robin archives (RRRRRRRRAAAA). An archive consists of a
             number of data values from all the defined data-
             sources (DDDDSSSS) and is defined with an RRRRRRRRAAAA line.

             When data is entered into an RRRRRRRRDDDD, it is first fit
             into time slots of the length defined with the ----ssss
             option becoming a _p_r_i_m_a_r_y _d_a_t_a _p_o_i_n_t.

             The data is also consolidated with the consolidation
             function (_C_F) of the archive. The following
             consolidation functions are defined: AAAAVVVVEEEERRRRAAAAGGGGEEEE, MMMMIIIINNNN,
             MMMMAAAAXXXX, LLLLAAAASSSSTTTT.

             _x_f_f The xfiles factor defines what part of a
             consolidation interval may be made up from _*_U_N_K_N_O_W_N_*
             data while the consolidated value is still regarded
             as known.

             _s_t_e_p_s defines how many of these _p_r_i_m_a_r_y _d_a_t_a _p_o_i_n_t_s
             are used to build a _c_o_n_s_o_l_i_d_a_t_e_d _d_a_t_a _p_o_i_n_t which
             then goes into the archive.

             _r_o_w_s defines how many generations of data values are
             kept in an RRRRRRRRAAAA.

TTTThhhheeee HHHHEEEEAAAARRRRTTTTBBBBEEEEAAAATTTT aaaannnndddd tttthhhheeee SSSSTTTTEEEEPPPP
     Here is an explanation by Don Baarda on the inner workings
     of rrdtool.  It may help you to sort out why all this
     *UNKNOWN* data is popping up in your databases:

     RRD gets fed samples at arbitrary times. From these it
     builds Primary Data Points (PDPs) at exact times every
     "step" interval. The PDPs are then accumulated into RRAs.

     The "heartbeat" defines the maximum acceptable interval
     between samples. If the interval between samples is less
     than "heartbeat", then an average rate is calculated and
     applied for that interval. If the interval between samples
     is longer than "heartbeat", then that entire interval is
     considered "unknown". Note that there are other things that
     can make a sample interval "unknown", such as the rate
     exceeding limits, or even an "unknown" input sample.

     The known rates during a PDP's "step" interval are used to
     calculate an average rate for that PDP. Also, if the total
     "unknown" time during the "step" interval exceeds the
     "heartbeat", the entire PDP is marked as "unknown". This
     means that a mixture of known and "unknown" sample time in a
     single PDP "step" may or may not add up to enough "unknown"
     time to exceed "heartbeat" and hence mark the whole PDP



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rrdtool                                              RRDCREATE(1)



     "unknown". So "heartbeat" is not only the maximum acceptable
     interval between samples, but also the maximum acceptable
     amount of "unknown" time per PDP (obviously this is only
     significant if you have "heartbeat" less than "step").

     The "heartbeat" can be short (unusual) or long (typical)
     relative to the "step" interval between PDPs. A short
     "heartbeat" means you require multiple samples per PDP, and
     if you don't get them mark the PDP unknown. A long heartbeat
     can span multiple "steps", which means it is acceptable to
     have multiple PDPs calculated from a single sample. An
     extreme example of this might be a "step" of 5mins and a
     "heartbeat" of one day, in which case a single sample every
     day will result in all the PDPs for that entire day period
     being set to the same average rate. _-_- _D_o_n _B_a_a_r_d_a
     _<_d_o_n_._b_a_a_r_d_a_@_b_a_e_s_y_s_t_e_m_s_._c_o_m_>

HHHHOOOOWWWW TTTTOOOO MMMMEEEEAAAASSSSUUUURRRREEEE
     Here are a few hints on how to measure:

     Temperature
         Normally you have some type of meter you can read to get
         the temperature.  The temperature is not realy connected
         with a time. The only connection is that the temperature
         reading happened at a certain time. You can use the
         GGGGAAAAUUUUGGGGEEEE data source type for this. RRRtool will the record
         your reading together with the time.

     Mail Messages
         Assume you have a methode to count the number of
         messages transported by your mailserver in a certain
         amount of time, this give you data like '5 messages in
         the last 65 seconds'. If you look at the count of 5 like
         and AAAABBBBSSSSOOOOLLLLUUUUTTTTEEEE datatype you can simply update the rrd with
         the number 5 and the end time of your monitoring period.
         RRDtool will then record the number of messages per
         second. If at some later stage you want to know the
         number of messages transported in a day, you can get the
         average messages per second from RRDtool for the day in
         question and multiply this number with the number of
         seconds in a day. Because all math is run with Doubles,
         the precision should be acceptable.

     It's always a Rate
         RRDtool stores rates in amount/second for COUNTER,
         DERIVE and ABSOLUTE data.  When you plot the data, you
         will get on the y axis amount/second which you might be
         tempted to convert to absolute amount volume by
         multiplying by the delta-time between the points.
         RRDtool plots continuous data, and as such is not
         appropriate for plotting absolute volumes as for example
         "total bytes" sent and received in a router. What you



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rrdtool                                              RRDCREATE(1)



         probably want is plot rates that you can scale to for
         example bytes/hour or plot volumes with another tool
         that draws bar-plots, where the delta-time is clear on
         the plot for each point (such that when you read the
         graph you see for example GB on the y axis, days on the
         x axis and one bar for each day).

EEEEXXXXAAAAMMMMPPPPLLLLEEEE
     `rrdtool create temperature.rrd --step 300
     DS:temp:GAUGE:600:-273:5000 RRA:AVERAGE:0.5:1:1200
     RRA:MIN:0.5:12:2400 RRA:MAX:0.5:12:2400
     RRA:AVERAGE:0.5:12:2400'

     This sets up an RRRRRRRRDDDD called _t_e_m_p_e_r_a_t_u_r_e_._r_r_d which accepts one
     temperature value every 300 seconds. If no new data is
     supplied for more than 600 seconds, the temperature becomes
     _*_U_N_K_N_O_W_N_*.  The minimum acceptable value is -273 and the
     maximum is 5000.

     A few archives areas are also defined. The first stores the
     temperatures supplied for 100 hours (1200 * 300 seconds =
     100 hours). The second RRA stores the minimum temperature
     recorded over every hour (12 * 300 seconds = 1 hour), for
     100 days (2400 hours). The third and the fourth RRA's do the
     same with the for the maximum and average temperature,
     respectively.

AAAAUUUUTTTTHHHHOOOORRRR
     Tobias Oetiker <oetiker@ee.ethz.ch>


























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