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
+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.
=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 spcific RRD file from memory. Check L<rrdflush>.
=item B<rrdcgi>
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 realy 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
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>