rrdupdate(1): Move the examples and document `updatev's behavior.

[rrdtool.git] / doc / rrdupdate.pod

diff --git a/doc/rrdupdate.pod b/doc/rrdupdate.pod
index cc0b452..91752ef 100644 (file)
--- a/doc/rrdupdate.pod
+++ b/doc/rrdupdate.pod
@@ -6,6 +6,8 @@ rrdupdate - Store a new set of values into the RRD
 
 B<rrdtool> {B<update> | B<updatev>} I<filename>
 S<[B<--template>|B<-t> I<ds-name>[B<:>I<ds-name>]...]>
+S<[B<-->[B<no>]B<cache>]>
+S<[B<--daemon> I<address>]>
 S<B<N>|I<timestamp>B<:>I<value>[B<:>I<value>...]>
 S<I<at-timestamp>B<@>I<value>[B<:>I<value>...]>
 S<[I<timestamp>B<:>I<value>[B<:>I<value>...] ...]>
@@ -29,6 +31,9 @@ RRA (consolidation function and PDPs per CDP), and data source (name).
 Note that depending on the arguments of the current and previous call to
 update, the list may have no entries or a large number of entries.
 
+Since B<updatev> requires direct disk access, the options B<--[no]cache> and
+B<--daemon> cannot be used with this command.
+
 =item I<filename>
 
 The name of the B<RRD> you want to update.
@@ -56,6 +61,26 @@ function. If this is done accidentally (and this can only be done
 using the template switch), B<RRDtool> will ignore the value specified
 for the COMPUTE B<DST>.
 
+=item B<--cache> | B<--nocache>
+
+Force the use of the caching daemon or force direct file access. If B<--cache>
+is given, B<RRDTool> will try to contact the caching daemon B<RRDd> and will
+fail if it cannot connect to the daemon. If the connection is successfully
+established the values will be sent to the daemon instead of accessing the
+files directly. If B<--nocache> is given no connection attempt is made. If
+neither option is specified B<RRDTool> will try to contact the daemon and, if
+no connection may be established, will fall back to direct file access.
+This option is available for the B<update> command only.
+
+=item B<--daemon> I<address>
+
+Specifies the address of the caching daemon. If I<address> begins with C<unix:>
+the everything after this prefix will be considered to be a UNIX domain socket.
+Otherwise the address is interpreted as network address or node name as
+understood by L<getaddrinfo(3)>. One practical consequence is that both, IPv4
+and IPv6, may be used if the system supports it.
+This option is available for the B<update> command only.
+
 =item B<N>|I<timestamp>B<:>I<value>[B<:>I<value>...]
 
 The data used for updating the RRD was acquired at a certain
@@ -82,20 +107,50 @@ separator.
 
 =back
 
-=head1 EXAMPLE
+=head1 EXAMPLES
+
+=over 4
+
+=item
 
 C<rrdtool update demo1.rrd N:3.44:3.15:U:23>
 
 Update the database file demo1.rrd with 3 known and one I<*UNKNOWN*>
 value. Use the current time as the update time.
 
+=item
+
 C<rrdtool update demo2.rrd 887457267:U 887457521:22 887457903:2.7>
 
 Update the database file demo2.rrd which expects data from a single
 data-source, three times. First with an I<*UNKNOWN*> value then with two
 regular readings. The update interval seems to be around 300 seconds.
 
-=head1 AUTHOR
+=item
+
+C<rrdtool update --cache /var/lib/rrd/demo3.rrd N:42>
+
+Update the file C</var/lib/rrd/demo3.rrd> with a single data source, using the
+current time. If the caching daemon cannot be reached, do B<not> fall back to
+direct file access.
+
+=item
+
+C<rrdtool update --daemon unix:/tmp/rrdd.sock demo4.rrd N:23>
+
+Use the UNIX domain socket C</tmp/rrdd.sock> to contact the caching daemon. If
+the caching daemon is not available, update the file C<demo4.rrd> directly.
+B<WARNING:> Since a relative path is specified, the following disturbing effect
+may occur: If the daemon is available, the file relative to the working
+directory B<of the daemon> is used. If the daemon is not available, the file
+relative to the current working directory of the invoking process is used.
+B<This may update two different files depending on whether the daemon could be
+reached or not.> Don't do relative paths, kids!
+
+=back
+
+=head1 AUTHORS
 
-Tobias Oetiker <tobi@oetiker.ch>
+Tobias Oetiker <tobi@oetiker.ch>,
+Florian Forster <octoE<nbsp>atE<nbsp>verplant.org>