Now let's go back to the first example of multiple logic operators,
but replace the value 20 with the variable "input":
-=for comment
-XXX wo kommt das A ploetzlich her? Hier braucht es einen Satz, dass A als
-XXX placeholder zum Lesbarmachen verwendet wird (shortcut).
-
- 1) input,10,GT,10,input,IF eval is input,10,GT result is A
+ 1) input,10,GT,10,input,IF eval is input,10,GT ( lets call this A )
Read eval as "if input > 10 then true" and replace "input,10,GT"
with "A":
=item RRD::GRAPH I<rrdgraph arguments>
-=for comment
-XXX Shouldn't it be IMAGE-tag below? Fritz
-
This tag creates the RRD graph defined by its argument and then is
-replaced by an appropriate E<lt>IMGE<gt> tag referring to the graph.
+replaced by an appropriate E<lt>IMG ... E<gt> tag referring to the graph.
The B<--lazy> option in RRD graph can be used to make sure that graphs
are only regenerated when they are out of date. The arguments
to the B<RRD::GRAPH> tag work as described in the B<rrdgraph> manual page.
including B<midnight> (00:00), B<noon> (12:00) and British
B<teatime> (16:00).
-=for comment
-XXX Wouldn't it be nice to have z'N\"uni and z'Vieri for Switzerland?
-
-The I<day> can be specified as I<month-name> I<day-of-the-month>
-and optional a 2- or 4-digit I<year> number (e.g. March 8 1999).
-Alternatively, you can use I<day-of-week-name> (e.g. Monday),
-or one of the words: B<yesterday>, B<today>, B<tomorrow>.
-You can also specify the I<day> as a full date in several numerical formats, including B<MM/DD/[YY]YY>, B<DD.MM.[YY]YY>, or B<YYYYMMDD>.
+The I<day> can be specified as I<month-name> I<day-of-the-month> and
+optional a 2- or 4-digit I<year> number (e.g. March 8 1999). Alternatively,
+you can use I<day-of-week-name> (e.g. Monday), or one of the words:
+B<yesterday>, B<today>, B<tomorrow>. You can also specify the I<day> as a
+full date in several numerical formats, including B<MM/DD/[YY]YY>,
+B<DD.MM.[YY]YY>, or B<YYYYMMDD>.
I<NOTE1>: this is different from the original at(1) behavior, where a
single-number date is interpreted as MMDD[YY]YY.
a resolution of 1800 seconds per B<CDP>, you should create an
image with width 400 and time span 400*1800 seconds (use appropriate
start and end times, such as C<--start end-8days8hours>).
-=for comment
-XXX is the above start/end syntax correct? Fritz
If consolidation needs to be done, the B<CF> of the B<RRA> specified in the
B<DEF> itself will be used to reduce the data density. This behaviour can
COMMENT:" "
-=for comment
-XXX I don't understand the following; Fritz
-
-Note: three times size == 11 chars, "###.## xBps"
+Note: the column titles have to be as wide as the columns
COMMENT:"Maximum "
COMMENT:"Average "
=cut
+#### This section describes the curruently defunct
+#### PieChart code.
+
=item B<PART>B<:>I<vname>B<#>I<rrggbb>[I<aa>][B<:>I<legend>]
B<RRDtool> has now support for B<pie charts>. If you include the
function. It should return a number between 0 and 100, being a
percentage. Providing wrong input will produce undefined results.
-=for comment
-XXX Above: shouldn't this be caught and and error be generated? Fritz
+####
+####
=pod
B<MIN, MAX>
Pops two elements from the stack and returns the smaller or larger,
-respectively. The two numbers shouldn't be I<infinite> or I<unknown>,
-if they are that value is pushed back onto the stack as the result.
-
-= for comment
-XXX What happens above if both a infinite and undefined value are on the
-XXX stack? Fritz
+respectively. Note that I<infinite> is larger than anything else.
+If one of the input numbers is I<unknown> then the result of the operation will be
+I<unknown> too.
B<LIMIT>
=head2 What data can be put into an RRD?
-XXX time series ??? XXX You name it, it will probably fit. You should
-be able to measure some value at several points in time and provide
-this information to RRDtool. If you can do this, RRDtool will be able
-to store it. The values must be numerical but don't have to be
-integers, as is the case with MRTG (the next section will give more
-details on this more specialized application).
+You name it, it will probably fit as long as it is some sort of time-series
+data. This means you have to be able to measure some value at several points in time and
+provide this information to RRDtool. If you can do this, RRDtool will be
+able to store it. The values must be numerical but don't have to be
+integers, as is the case with MRTG (the next section will give more details
+on this more specialized application).
Many examples below talk about SNMP which is an acronym for Simple Network
Management Protocol. "Simple" refers to the protocol -- it does not
(default). In the same database two round robin archives (RRAs) are
kept, one averages the data every time it is read (e.g., there's
nothing to average) and keeps 24 samples (24 times 5 minutes is 2
-hours). The other averages 6 values (half hour) and contains 10 of
+hours). The other averages 6 values (half hour) and contains 10
such averages (e.g., 5 hours).
-=for comment
- XXX The remaining options will be discussed later on. (there aren't any
- XXX in the example above, Fritz)
-
RRDtool works with special time stamps coming from the UNIX world.
This time stamp is the number of seconds that passed since January
1st 1970 UTC. The time stamp value is translated into local time and
Hang on! If we can multiply values with 1'000, it should also be possible
to display kilometers per hour from the same data!
-=for comment
-XXX strange format below: -*- ; Fritz
-
To change a value that is measured in meters per second:
- -*- Calculate meters per hour: value * 3'600
- -*- Calculate kilometers per hour: value / 1'000
- -*- Together this makes: value * (3'600/1'000) or value * 3.6
+
+ Calculate meters per hour: value * 3'600
+ Calculate kilometers per hour: value / 1'000
+ Together this makes: value * (3'600/1'000) or value * 3.6
In our example database we made a mistake and we need to compensate for
this by multiplying with 1'000. Applying that correction:
- -*- value * 3.6 * 1'000 == value * 3'600
+
+ value * 3.6 * 1'000 == value * 3'600
Now let's create this PNG, and add some more magic ...
- rrdtool graph speed3.png \
+ rrdtool graph speed3.png \
--start 920804400 --end 920808000 \
--vertical-label km/h \
DEF:myspeed=test.rrd:speed:AVERAGE \
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