RRDTOOL(1)                   rrdtool                   RRDTOOL(1)



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       rrdtool - round robin database tool

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       rrrrrrrrddddttttoooooooollll ---- | _f_u_n_c_t_i_o_n

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       OOOOVVVVEEEERRRRVVVVIIIIEEEEWWWW

       It is pretty easy to gather status information from all
       sorts of things, ranging from the temperature in your
       office to the number of octets which have passed through
       the FDDI interface of your router. But it is not so triv-
       ial to store this data in a efficient and systematic man-
       ner. This is where rrrrrrrrddddttttoooooooollll kicks in. It lets you _l_o_g _a_n_d
       _a_n_a_l_y_z_e the data you gather from all kinds of data-sources
       (DDDDSSSS). The data analysis part of rrdtool is based on the
       ability to quickly generate graphical representations of
       the data values collected over a definable time period.

       In this man page you will find general information on the
       design and functionality of the Round Robin Database Tool
       (rrdtool). For a more detailed description of how to use
       the individual functions of the rrrrrrrrddddttttoooooooollll check the corre-
       sponding man page.

       For an introduction to the usage of rrdtool make sure you
       check the rrdtutorial manpage.

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       While the man pages talk of command line switches you have
       to set in order to make rrrrrrrrddddttttoooooooollll work it is important to
       note that the rrrrrrrrddddttttoooooooollll can be 'remote controlled' through a
       set of pipes. This saves a considerable amount of startup
       time when you plan to make rrrrrrrrddddttttoooooooollll do a lot of things
       quickly. Check the section on the section on "Remote Con-
       trol" further down. There is also a number of language
       bindings for rrdtool which allow you to use it directly
       from perl, python, tcl, php, ...

       ccccrrrreeeeaaaatttteeee  Set up a new Round Robin Database (RRD). Check the
               rrdcreate manpage.

       uuuuppppddddaaaatttteeee  Store new data values into an RRD. Check the
               rrdupdate manpage.

       ggggrrrraaaapppphhhh   Create a graph from data stored in one or several
               RRD. Apart from generating graphs, data can also
               be extracted to stdout. Check the rrdgraph man-
               page.

       dddduuuummmmpppp    Dump the contents of an RRD in plain ASCII. In
               connection with restore you can use it to trans-
               port an rrd from one architecture to another.
               Check the rrddump manpage.

       rrrreeeessssttttoooorrrreeee Restore an RRD in XML format to a binary rrd ...
               Check the rrdrestore manpage

       ffffeeeettttcccchhhh   Get data for a certain time period from a RRD. The
               graph function uses fetch to retrieve its data
               from an rrd. Check the rrdfetch manpage.

       ttttuuuunnnneeee    Alter setup of an RRD. Check the rrdtune manpage.

       llllaaaasssstttt    Find last update time of an RRD. Check the rrdlast
               manpage.

       rrrrrrrrddddrrrreeeessssiiiizzzzeeee
               Change the size of individual RRAs ... Dangerous!
               Check the rrdresize manpage.

       rrrrrrrrddddccccggggiiii  This is a standalone tool for producing rrd graphs
               on the fly. Check the rrdcgi manpage.

       HHHHOOOOWWWW DDDDOOOOEEEESSSS RRRRRRRRDDDDTTTTOOOOOOOOLLLL WWWWOOOORRRRKKKK????


       Data acquisition
               When monitoring the state of a system, it is con-
               venient to have the data available at a constant
               interval. Unfortunately you may not always be able
               to fetch data at exactly the time you want to.
               Therefore rrrrrrrrddddttttoooooooollll lets you update the logfile at
               any time you want. It will automatically interpo-
               late the value of the data-source (DDDDSSSS) at the lat-
               est official time-slot and write this value to the
               log. The value you have supplied is stored as well
               and is also taken into account when interpolating
               the next log entry.

       Consolidation
               You may log data at a 1 minute interval, but you
               are also be interested to know the development of
               the data over the last year. You could do this by
               simply storing the data in 1 minute interval, for
               one year. While this would take considerable disk
               space it would also take a lot of time to analyze
               the data when you wanted to create a graph cover-
               ing the whole year. rrrrrrrrddddttttoooooooollll offers a solution to
               this of this problem through its data consolida-
               tion feature. When setting up an Round Robin
               Database (RRRRRRRRDDDD), you can define at which interval
               this consolidation should occur, and what consoli-
               dation function (CCCCFFFF) (average, minimum, maximum,
               total, last) should be used to build the consoli-
               dated values (see rrdcreate). You can define any
               number of different consolidation setups within
               one RRRRRRRRDDDD. They will all be maintained on the fly
               when new data is loaded into the RRRRRRRRDDDD.

       Round Robin Archives
               Data values of the same consolidation setup are
               stored into Round Robin Archives (RRRRRRRRAAAA). This is a
               very efficient manner to store data for a certain
               amount of time, while using a known amount of
               storage space.

               It works like this: If you want to store 1000 val-
               ues in 5 minute interval, rrrrrrrrddddttttoooooooollll will allocate
               space for 1000 data values and a header area. In
               the header it will store a pointer telling which
               one of the values in the storage area was last
               written to. New values are written to the Round
               Robin Archive in a ...  you guess it ... round
               robin manner. This automatically limits the his-
               tory to the last 1000 values. Because you can
               define several RRRRRRRRAAAAs within a single RRRRRRRRDDDD, you can
               setup another one, storing 750 data values at a 2
               hour interval and thus keeping a log for the last
               two months although at a lower resolution.

               The use of RRRRRRRRAAAAs guarantees that the RRRRRRRRDDDD does not
               grow over time and that old data is automatically
               eliminated. By using the consolidation feature,
               you can still keep data for a very long time,
               while gradually reducing the resolution of the
               data along the time axis. Using different consoli-
               dation functions (CCCCFFFF) allows you to store exactly
               the type of information that actually interests
               you. (Maximum one minute traffic on the LAN, mini-
               mum temperature of the wine cellar, total minutes
               down time ...)

       Unknown Data
               As mentioned earlier, the RRRRRRRRDDDD stores data at a
               constant interval. Now it may happen that no new
               data is available when a value has to be written
               to the RRRRRRRRDDDD. Data acquisition may not be possible
               for one reason or an other. The rrrrrrrrddddttttoooooooollll handles
               these situations by storing an _*_U_N_K_N_O_W_N_* value
               into the database. The value '_*_U_N_K_N_O_W_N_*' is sup-
               ported through all the functions of the database.
               When consolidating the amount of _*_U_N_K_N_O_W_N_* data is
               accumulated and when a new consolidated value is
               ready to be written to its Round Robin Archive
               (RRRRRRRRAAAA) a validity check is performed to make sure
               that the percentage of unknown data in the new
               value is below a configurable level. If so, an
               _*_U_N_K_N_O_W_N_* value will be written to the RRRRRRRRAAAA.

       Graphing
               The rrrrrrrrddddttttoooooooollll also allows one to generate reports in
               numerical and graphical form based on the data
               stored in one or several RRRRRRRRDDDDs. The graphing fea-
               ture is fully configurable. Size, color and con-
               tents of the graph can be defined freely. Check
               the rrdgraph manpage for more information on this.

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       When you start rrrrrrrrddddttttoooooooollll with the command line option '----',
       it waits for input via standard in. With this feature you
       can improve performance by attaching rrrrrrrrddddttttoooooooollll to another
       process (mrtg is one example) through a set of pipes. Over
       the pipes rrrrrrrrddddttttoooooooollll accepts the same arguments as on the
       command line. When a command is completed, rrdtool will
       print the string  '`OK'', followed by timing information
       of the form uuuu::::_u_s_e_r_t_i_m_e ssss::::_s_y_s_t_e_m_t_i_m_e both values are run-
       ning totals of seconds since rrdtool was started. If an
       error occurs, a line of the form '`ERROR:' _D_e_s_c_r_i_p_t_i_o_n _o_f
       _e_r_r_o_r' will be printed. rrrrrrrrddddttttoooooooollll will not abort if possi-
       ble, but follow the ERROR line with an OK line.

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       rrdcreate, rrdupdate, rrdgraph, rrddump, rrdfetch, rrd-
       tune, rrdlast

BBBBUUUUGGGGSSSS
       Bugs ? Features !

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



