=head1 NAME rrdtool tune - Modify some basic properties of a Round Robin Database =for html
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=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]> =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*. The main 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. =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<--data-source-rename>|B<-r> I:I]> rename a data source =back =head1 EXAMPLE 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 AUTHOR Tobias Oetiker