B<rrdtool> B<create> I<filename>
S<[B<--start>|B<-b> I<start time>]>
S<[B<--step>|B<-s> I<step>]>
+S<[B<--no-overwrite>]>
S<[B<DS:>I<ds-name>B<:>I<DST>B<:>I<dst arguments>]>
S<[B<RRA:>I<CF>B<:>I<cf arguments>]>
Specifies the base interval in seconds with which data will be fed
into the B<RRD>.
+=head2 B<--no-overwrite>
+
+Do not clobber an existing file of the same name.
+
=head2 B<DS:>I<ds-name>B<:>I<DST>B<:>I<dst arguments>
A single B<RRD> can accept input from several data sources (B<DS>),
more than B<half> the "step", the entire PDP is marked
as "unknown". This means that a mixture of known and "unknown" sample
times in a single PDP "step" may or may not add up to enough "known"
-time to warrent for a known PDP.
+time to warrant a known PDP.
The "heartbeat" can be short (unusual) or long (typical) relative to
the "step" interval between PDPs. A short "heartbeat" means you
=item Mail Messages
Assume you have a method to count the number of messages transported by
-your mailserver in a certain amount of time, giving you data like '5
+your mail server in a certain amount of time, giving you data like '5
messages in the last 65 seconds'. If you look at the count of 5 like an
B<ABSOLUTE> data type you can simply update the RRD with the number 5 and the
end time of your monitoring period. RRDtool will then record the number of