order to make B<RRDtool> work it is important to note that
B<RRDtool> can be remotely controlled through a set of pipes. This
saves a considerable amount of startup time when you plan to make
-B<RRDtool> do a lot of things quickly. Check the section on L<"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, etc.
+B<RRDtool> do a lot of things quickly. Check the section on L<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, etc.
=over 8
=item B<xport>
-Export data retrieved from one or several RRDs. Check L<rrdxport>
+Export data retrieved from one or several RRDs. Check L<rrdxport>.
+
+=item B<flush>
+
+Flush the values for a specific RRD file from memory. Check L<rrdflush>.
=item B<rrdcgi>
always be able to fetch data at exactly the time you want
to. Therefore B<RRDtool> lets you update the logfile at any time you
want. It will automatically interpolate the value of the data-source
-(B<DS>) at the latest official time-slot (intervall) and write this
+(B<DS>) at the latest official time-slot (interval) and write this
interpolated value to the log. The original value you have supplied is
stored as well and is also taken into account when interpolating the
next log entry.
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.
+axis.
Using different consolidation functions (B<CF>) allows you to store
exactly the type of information that actually interests you: the maximum
commands like B<quit, cd, mkdir> and B<ls>. For detailed help on the
server commands type:
- rrdtool help cd|mkdir|ls|quit
+ rrdtool help cd|mkdir|pwd|ls|quit
-When a command is completed, RRDtool will print the string 'C<OK>',
-followed by timing information of the form B<u:>I<usertime>
-B<s:>I<systemtime>. Both values are the running totals of seconds
-since RRDtool was started. If an error occurs, a line of the
-form 'C<ERROR:> I<Description of error>' will be printed. B<RRDtool>
-will not abort, if possible, but follow the ERROR line with an OK line.
-If a B<workdir> is specified and the UID is 0, RRDtool will do a
-chroot to that workdir. If the UID is not 0, RRDtool only changes the
-current directory to B<workdir>.
+When a command is completed, RRDtool will print the string 'C<OK>',
+followed by timing information of the form B<u:>I<usertime>
+B<s:>I<systemtime>. Both values are the running totals of seconds since
+RRDtool was started. If an error occurs, a line of the form 'C<ERROR:>
+I<Description of error>' will be printed instead. B<RRDtool> will not abort,
+unless something really serious happens. If
+a B<workdir> is specified and the UID is 0, RRDtool will do a chroot to that
+workdir. If the UID is not 0, RRDtool only changes the current directory to
+B<workdir>.
=head2 RRD Server
-If you want to create a RRD-Server, you must choose a TCP/IP Service
+If you want to create a RRD-Server, you must choose a TCP/IP Service
number and add them to I</etc/services> like this:
rrdsrv 13900/tcp # RRD server
With this configuration you can add RRDtool as meta-server to
I</etc/inetd.conf>. For example:
-
+
rrdsrv stream tcp nowait root /opt/rrd/bin/rrdtool rrdtool - /var/rrd
Don't forget to create the database directory /var/rrd and
reinitialize your inetd.
-If all was setup correctly, you can access the server with perl
+If all was setup correctly, you can access the server with Perl
sockets, tools like netcat, or in a quick interactive test by using
'telnet localhost rrdsrv'.
-<B>NOTE</B> that there is no authentication with this feature! Do not setup
+B<NOTE:> that there is no authentication with this feature! Do not setup
such a port unless you are sure what you are doing.
+=head1 RRDCACHED, THE CACHING DAEMON
+
+For very big setups, updating thousands of RRD files often becomes a serious IO
+problem. If you run into such problems, you might want to take a look at
+L<rrdcached>, a caching daemon for RRDTool which may help you lessen the
+stress on your disks.
+
=head1 SEE ALSO
-rrdcreate, rrdupdate, rrdgraph, rrddump, rrdfetch, rrdtune, rrdlast, rrdxport
+rrdcreate, rrdupdate, rrdgraph, rrddump, rrdfetch, rrdtune, rrdlast, rrdxport,
+rrdflush, rrdcached
=head1 BUGS
=head1 AUTHOR
-Tobias Oetiker <oetiker@ee.ethz.ch>
+Tobias Oetiker <tobi@oetiker.ch>
projects / rrdtool.git / blobdiff