


 RRRRRRRRDDDDTTTTOOOOOOOOLLLL((((1111))))                        1111....0000....44445555                         RRRRRRRRDDDDTTTTOOOOOOOOLLLL((((1111))))
 rrrrrrrrddddttttoooooooollll                                                             rrrrrrrrddddttttoooooooollll
                                 2222000000002222----11111111----22229999



 NNNNAAAAMMMMEEEE
      rrdtool - round robin database tool

 SSSSYYYYNNNNOOOOPPPPSSSSIIIISSSS
      rrrrrrrrddddttttoooooooollll ---- | _f_u_n_c_t_i_o_n

 DDDDEEEESSSSCCCCRRRRIIIIPPPPTTTTIIIIOOOONNNN
      OOOOVVVVEEEERRRRVVVVIIIIEEEEWWWW

      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 trivial to store this data in a efficient and
      systematic manner. This is where rrrrrrrrddddttttoooooooollll 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 (DDDDSSSS). 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
      rrrrrrrrddddttttoooooooollll check the corresponding man page.

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

      FFFFUUUUNNNNCCCCTTTTIIIIOOOONNNNSSSS

      While the man pages talk of command line switches you have to set in
      order to make rrrrrrrrddddttttoooooooollll work it is important to note that the rrrrrrrrddddttttoooooooollll
      can be 'remote controlled' through a set of pipes. This saves a
      considerable amount of startup time when you plan to make rrrrrrrrddddttttoooooooollll do a
      lot of things quickly. Check the section on "Remote Control" further
      down. There is also a number of language bindings for rrdtool which
      allow you to use it directly from perl, python, tcl, php, ...

      ccccrrrreeeeaaaatttteeee  Set up a new Round Robin Database (RRD). Check rrdcreate.

      uuuuppppddddaaaatttteeee  Store new data values into an RRD. Check rrdupdate.

      ggggrrrraaaapppphhhh   Create a graph from data stored in one or several RRD. Apart
              from generating graphs, data can also be extracted to stdout.
              Check rrdgraph.

      dddduuuummmmpppp    Dump the contents of an RRD in plain ASCII. In connection with
              restore you can use it to transport an rrd from one
              architecture to another.  Check rrddump.

      rrrreeeessssttttoooorrrreeee Restore an RRD in XML format to a binary rrd ... Check



                                    - 1 -        Formatted:  August 20, 2003






 RRRRRRRRDDDDTTTTOOOOOOOOLLLL((((1111))))                        1111....0000....44445555                         RRRRRRRRDDDDTTTTOOOOOOOOLLLL((((1111))))
 rrrrrrrrddddttttoooooooollll                                                             rrrrrrrrddddttttoooooooollll
                                 2222000000002222----11111111----22229999



              rrdrestore

      ffffeeeettttcccchhhh   Get data for a certain time period from a RRD. The graph
              function uses fetch to retrieve its data from an rrd. Check
              rrdfetch.

      ttttuuuunnnneeee    Alter setup of an RRD. Check rrdtune.

      llllaaaasssstttt    Find last update time of an RRD. Check rrdlast.

      iiiinnnnffffoooo    Display information about an RRD ... Check rrdinfo

      rrrrrrrrddddrrrreeeessssiiiizzzzeeee
              Change the size of individual RRAs ... Dangerous! Check
              rrdresize.

      xxxxppppoooorrrrtttt   Export data retrieved from one or several RRD. Check rrdxport

      rrrrrrrrddddccccggggiiii  This is a standalone tool for producing rrd graphs on the fly.
              Check rrdcgi.

      HHHHOOOOWWWW DDDDOOOOEEEESSSS RRRRRRRRDDDDTTTTOOOOOOOOLLLL WWWWOOOORRRRKKKK????

      Data acquisition
              When monitoring the state of a system, it is convenient 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 rrrrrrrrddddttttoooooooollll lets you update the logfile at
              any time you want. It will automatically interpolate the value
              of the data-source (DDDDSSSS) at the latest 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 covering the whole
              year. rrrrrrrrddddttttoooooooollll offers a solution to this problem through its
              data consolidation feature. When setting up an Round Robin
              Database (RRRRRRRRDDDD), you can define at which interval this
              consolidation should occur, and what consolidation function
              (CCCCFFFF) (average, minimum, maximum, last) should be used to build
              the consolidated values (see rrdcreate). You can define any
              number of different consolidation setups within one RRRRRRRRDDDD. They
              will all be maintained on the fly when new data is loaded into
              the RRRRRRRRDDDD.



                                    - 2 -        Formatted:  August 20, 2003






 RRRRRRRRDDDDTTTTOOOOOOOOLLLL((((1111))))                        1111....0000....44445555                         RRRRRRRRDDDDTTTTOOOOOOOOLLLL((((1111))))
 rrrrrrrrddddttttoooooooollll                                                             rrrrrrrrddddttttoooooooollll
                                 2222000000002222----11111111----22229999



      Round Robin Archives
              Data values of the same consolidation setup are stored into
              Round Robin Archives (RRRRRRRRAAAA). 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 values in 5
              minute interval, rrrrrrrrddddttttoooooooollll 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 history to the last 1000 values.
              Because you can define several RRRRRRRRAAAAs within a single RRRRRRRRDDDD, 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 RRRRRRRRAAAAs guarantees that the RRRRRRRRDDDD 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 consolidation functions
              (CCCCFFFF) allows you to store exactly the type of information that
              actually interests you. (Maximum one minute traffic on the
              LAN, minimum temperature of the wine cellar, total minutes
              down time ...)

      Unknown Data
              As mentioned earlier, the RRRRRRRRDDDD 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 RRRRRRRRDDDD. Data acquisition may not
              be possible for one reason or an other. The rrrrrrrrddddttttoooooooollll 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 supported 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 (RRRRRRRRAAAA)
              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 RRRRRRRRAAAA.

      Graphing
              The rrrrrrrrddddttttoooooooollll also allows one to generate reports in numerical
              and graphical form based on the data stored in one or several
              RRRRRRRRDDDDs. The graphing feature is fully configurable. Size, color
              and contents of the graph can be defined freely. Check
              rrdgraph for more information on this.





                                    - 3 -        Formatted:  August 20, 2003






 RRRRRRRRDDDDTTTTOOOOOOOOLLLL((((1111))))                        1111....0000....44445555                         RRRRRRRRDDDDTTTTOOOOOOOOLLLL((((1111))))
 rrrrrrrrddddttttoooooooollll                                                             rrrrrrrrddddttttoooooooollll
                                 2222000000002222----11111111----22229999



      RRRREEEEMMMMOOOOTTTTEEEE CCCCOOOONNNNTTTTRRRROOOOLLLL

      When you start rrrrrrrrddddttttoooooooollll with the command line option '----', it waits for
      input via standard in. With this feature you can improve performance
      by attaching rrrrrrrrddddttttoooooooollll to another process (mrtg is one example) through
      a set of pipes. Over the pipes rrrrrrrrddddttttoooooooollll 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
      uuuu::::_u_s_e_r_t_i_m_e ssss::::_s_y_s_t_e_m_t_i_m_e both values are running 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. rrrrrrrrddddttttoooooooollll will not
      abort if possible, but follow the ERROR line with an OK line.

 SSSSEEEEEEEE AAAALLLLSSSSOOOO
      rrdcreate, rrdupdate, rrdgraph, rrddump, rrdfetch, rrdtune, rrdlast,
      rrdxport

 BBBBUUUUGGGGSSSS
      Bugs ? Features !

 AAAAUUUUTTTTHHHHOOOORRRR
      Tobias Oetiker <oetiker@ee.ethz.ch>































                                    - 4 -        Formatted:  August 20, 2003



