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<--daemon> I<address>]>
S<[B<DS:>I<ds-name>B<:>I<DST>B<:>I<dst arguments>]>
S<[B<RRA:>I<CF>B<:>I<cf arguments>]>
Database (B<RRD>) files. The file is created at its final, full size
and filled with I<*UNKNOWN*> data.
-=over 8
-
-=item I<filename>
+=head2 I<filename>
The name of the B<RRD> you want to create. B<RRD> files should end
with the extension F<.rrd>. However, B<RRDtool> will accept any
filename.
-=item B<--start>|B<-b> I<start time> (default: now - 10s)
+=head2 B<--start>|B<-b> I<start time> (default: now - 10s)
Specifies the time in seconds since 1970-01-01 UTC when the first
value should be added to the B<RRD>. B<RRDtool> will not accept
See also AT-STYLE TIME SPECIFICATION section in the
I<rrdfetch> documentation for other ways to specify time.
-=item B<--step>|B<-s> I<step> (default: 300 seconds)
+=head2 B<--step>|B<-s> I<step> (default: 300 seconds)
Specifies the base interval in seconds with which data will be fed
into the B<RRD>.
-=item B<DS:>I<ds-name>B<:>I<DST>B<:>I<dst arguments>
+=head2 B<--no-overwrite>
+
+Do not clobber an existing file of the same name.
+
+=item B<--daemon> I<address>
+
+Address of the L<rrdcached> daemon. For a list of accepted formats, see
+the B<-l> option in the L<rrdcached> manual.
+
+ rrdtool create --daemon unix:/var/run/rrdcached.sock /var/lib/rrd/foo.rrd I<other options>
+
+=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>),
for example incoming and outgoing traffic on a specific communication
definitions that follow. Also consult the section on "HOW TO MEASURE"
for further insight.
-=over 4
+=over
=item B<GAUGE>
overflow checks. So if your counter does not reset at 32 or 64 bit you
might want to use DERIVE and combine it with a MIN value of 0.
-=over
-
-=item NOTE on COUNTER vs DERIVE
+B<NOTE on COUNTER vs DERIVE>
by Don Baarda E<lt>don.baarda@baesystems.comE<gt>
setting will eliminate the possibility of mistaking a reset for a counter
wrap.
-=back
-
=item B<ABSOLUTE>
is for counters which get reset upon reading. This is used for fast counters
data source is assumed to be I<*UNKNOWN*>.
I<min> and I<max> define the expected range values for data supplied by a
-data source. If I<min> and/or I<max> any value outside the defined range
+data source. If I<min> and/or I<max> are specified any value outside the defined range
will be regarded as I<*UNKNOWN*>. If you do not know or care about min and
max, set them to U for unknown. Note that min and max always refer to the
processed values of the DS. For a traffic-B<COUNTER> type DS this would be
similar to the restriction that B<CDEF>s must refer only to B<DEF>s
and B<CDEF>s previously defined in the same graph command.
-=item B<RRA:>I<CF>B<:>I<cf arguments>
-
+=head2 B<RRA:>I<CF>B<:>I<cf arguments>
The purpose of an B<RRD> is to store data in the round robin archives
(B<RRA>). An archive consists of a number of data values or statistics for
a I<consolidated data point> which then goes into the archive.
I<rows> defines how many generations of data values are kept in an B<RRA>.
-
-=back
+Obviously, this has to be greater than zero.
=head1 Aberrant Behavior Detection with Holt-Winters Forecasting
It may help you to sort out why all this *UNKNOWN* data is popping
up in your databases:
-RRDtool gets fed samples at arbitrary times. From these it builds Primary
-Data Points (PDPs) at exact times on every "step" interval. The PDPs are
-then accumulated into RRAs.
+RRDtool gets fed samples/updates at arbitrary times. From these it builds Primary
+Data Points (PDPs) on every "step" interval. The PDPs are
+then accumulated into the RRAs.
The "heartbeat" defines the maximum acceptable interval between
-samples. If the interval between samples is less than "heartbeat",
+samples/updates. If the interval between samples is less than "heartbeat",
then an average rate is calculated and applied for that interval. If
the interval between samples is longer than "heartbeat", then that
entire interval is considered "unknown". Note that there are other
things that can make a sample interval "unknown", such as the rate
-exceeding limits, or even an "unknown" input sample.
+exceeding limits, or a sample that was explicitly marked as unknown.
The known rates during a PDP's "step" interval are used to calculate
-an average rate for that PDP. Also, if the total "unknown" time during
-the "step" interval exceeds the "heartbeat", the entire PDP is marked
+an average rate for that PDP. If the total "unknown" time accounts for
+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 "unknown"
-time to exceed "heartbeat" and hence mark the whole PDP "unknown". So
-"heartbeat" is not only the maximum acceptable interval between
-samples, but also the maximum acceptable amount of "unknown" time per
-PDP (obviously this is only significant if you have "heartbeat" less
-than "step").
+times in a single PDP "step" may or may not add up to enough "known"
+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
u|15|/ "swt" expired
u|16|
|17|----* sample4, restart "hb", create "pdp" for step1 =
- |18| / = unknown due to 10 "u" labled secs > "hb"
+ |18| / = unknown due to 10 "u" labled secs > 0.5 * step
|19| /
|20| /
|21|----* sample5, restart "hb"
=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
projects / rrdtool.git / blobdiff