=head1 NAME
rrdtool tune - Modify some basic properties of a Round Robin Database
=for html
=head1 SYNOPSIS
B B I
S<[B<--heartbeat>|B<-h> I:I]>
S<[B<--minimum>|B<-i> I:I]>
S<[B<--maximum>|B<-a> I:I]>
S<[B<--data-source-type>|B<-d> I:I]>
S<[B<--data-source-rename>|B<-r> I:I]>
S<[B<--deltapos> I]>
S<[B<--deltaneg> I]>
S<[B<--failure-threshold> I]>
S<[B<--window-length> I]>
S<[B<--alpha> I]>
S<[B<--beta> I]>
S<[B<--gamma> I]>
=head1 DESCRIPTION
The tune option allows you to alter some of the basic configuration
values stored in the header area of a Round Robin Database (B).
All these tunable parameters together decide when data fed into an
B is to be regarded as invalid. Invalid data is entered into the
database as *UNKNOWN*.
One application of the B function is to relax the
validation rules on an B. This allows to fill a new B with
data available in larger intervals than what you would normally want
to permit.
A second application of the B function is to set or alter parameters
used by the specialized function B for aberrant behavior detection.
=over 8
=item I
The name of the B you want to tune.
=item S|B<-h> I:I>
modify the I of a data source. By setting this to a high
value the rrd will accept things like one value per day ...
=item S|B<-i> I:I>
alter the minimum value acceptable as input from the data source.
Setting I to 'U' will disable this limit.
=item S|B<-a> I:I>
alter the maximum value acceptable as input from the data source.
Setting I to 'U' will disable this limit.
=item S|B<-d> I:I>
alter the type B of a data source.
=item S|B<-r> I:I>
rename a data source
=item S I>
Alter the deviation scaling factor for the upper bound of the confidence band
used internally to calculate violations for the FAILURES B. The default
value is 2. Note that this parameter is not related to graphing confidence
bounds, that scale factor is specified as a CDEV argument to generate a graph with
confidence bounds. It need agree with the value used internally by the FAILURES
B (although common sense dictates it should).
=item S I>
Alter the deviation scaling factor for the lower bound of the confidence band
used internally to calculate violations for the FAILURES B. The default
value is 2. As with B<--deltapos>, this argument is unrelated to the scale
factor chosen when graphing confidence bounds.
=item S I>
Alter the number of confidence bound violations that constitute a failure for
purposes of the FAILURES B. This must be an integer less than or equal to
the window length of the FAILURES B. This restriction is not verified by
the tune option, so one can reset failure-threshold and window-length
simultaneously. Setting this option will reset the count of violations to 0.
=item S I>
Alter the number of time points in the temporal window for determining failures.
This must be an integer greater than or equal to the window length of the
FAILURES B and less than or equal to 28. Setting this option will reset the
count of violations to 0.
=item S I>
Alter the intercept adaptation parameter for the Holt-Winters forecasting algorithm.
Must be between 0 and 1.
=item S I>
Alter the intercept adaptation parameter for the Holt-Winters forecasting algorithm.
Must be between 0 and 1.
=item S I>
Alter the seasonal coefficient and deviation adaptation parameters the SEASONAL and
DEVSEAONAL B. Must be between 0 and 1.
=back
=head1 EXAMPLE 1
C
Set the minimum required heartbeat for data sources 'in', 'out'
and 'through' to 10000 seconds which is a little over one day in data.rrd.
This would allow to feed old data from mrtg-2.0 right into
rrdtool without generating *UNKNOWN* entries.
=head1 EXAMPLE 2
C
If the FAILURES B is implicitly created, the default window-length is 9 and
the default failure-thresold is 7. This command now defines a failure as 3 or more
violations in a temporal window of 5 time points.
=head1 AUTHOR
Tobias Oetiker