X-Git-Url: https://git.octo.it/?a=blobdiff_plain;f=doc%2Frrdupdate.pod;h=797b8bd33a2e4112907939db55b7f1fb62bf0980;hb=ac29bccef8036fb1a7ba55458c86d8601fcc56f4;hp=f2cd070f3f66a869f76974ad8be2d10abd4b3735;hpb=1ed31d581dfed23377a61d4df88bb9c2b9b2c94b;p=rrdtool.git diff --git a/doc/rrdupdate.pod b/doc/rrdupdate.pod index f2cd070..797b8bd 100644 --- a/doc/rrdupdate.pod +++ b/doc/rrdupdate.pod @@ -12,9 +12,9 @@ S<[IB<:>I[B<:>I...] ...]> =head1 DESCRIPTION -The B function feeds new data values into an B. The -data gets time aligned according to the properties of the B to -which the data is written. +The B function feeds new data values into an B. The data +is time aligned (interpolated) according to the properties of the +B to which the data is written. =over 8 @@ -35,11 +35,12 @@ The name of the B you want to update. =item B<--template>|B<-t> I[B<:>I]... -by default, the B function expects the data input in the order -the data sources are defined in the RRD, excluding any COMPUTE data sources -(i.e. if the third data source B is COMPUTE, the third input value -will be mapped to the fourth data source in the B). This is not very -error resistant, as you might be sending the wrong data into a RRD. +By default, the B function expects its data input in the order +the data sources are defined in the RRD, excluding any COMPUTE data +sources (i.e. if the third data source B is COMPUTE, the third +input value will be mapped to the fourth data source in the B and +so on). This is not very error resistant, as you might be sending the +wrong data into an RRD. The template switch allows you to specify which data sources you are going to update and in which order. If the data sources specified in @@ -50,32 +51,34 @@ While it appears possible with the template switch to update data sources asynchronously, B implicitly assigns non-COMPUTE data sources missing from the template the I<*UNKNOWN*> value. -Do not specify a value for a COMPUTE B in the B function. If -this is done accidentally (and this can only be done using the template switch), -B will ignore the value specified for the COMPUTE B. +Do not specify a value for a COMPUTE B in the B +function. If this is done accidentally (and this can only be done +using the template switch), B will ignore the value specified +for the COMPUTE B. =item B|IB<:>I[B<:>I...] -The data used for updating the RRD was acquired at a certain time. This -time can either be defined in seconds since 1970-01-01. Or by using the -letter 'N' the update time is set to be the current time. Negative time -values are subtracted from the current time. -An AT_STYLE TIME SPECIFICATION (see the I documentation) may -also be used by delimiting the end of the time specification with the '@' character -instead of a ':'. -Getting the timing right to the second is especially -important when you are working with data-sources of type B, -B or B. - -The remaining elements of the argument are DS updates. The order of this list is -the same as the order the data sources were defined in the RRA. -If there is no data for a certain data-source, the letter -B (e.g., N:0.1:U:1) can be defined. - -The format of the value acquired from the data source is dependent of the -data source type chosen. Normally it will be numeric, but the data acquisition -modules may impose their very own parsing of this parameter as long as the colon -(B<:>) remains the data source value separator. +The data used for updating the RRD was acquired at a certain +time. This time can either be defined in seconds since 1970-01-01 or +by using the letter 'N', in which case the update time is set to be +the current time. Negative time values are subtracted from the current +time. An AT_STYLE TIME SPECIFICATION (see the I +documentation) may also be used by delimiting the end of the time +specification with the '@' character instead of a ':'. Getting the +timing right to the second is especially important when you are +working with data-sources of type B, B or +B. + +The remaining elements of the argument are DS updates. The order of +this list is the same as the order the data sources were defined in +the RRA. If there is no data for a certain data-source, the letter +B (e.g., N:0.1:U:1) can be specified. + +The format of the value acquired from the data source is dependent on +the data source type chosen. Normally it will be numeric, but the data +acquisition modules may impose their very own parsing of this +parameter as long as the colon (B<:>) remains the data source value +separator. =back @@ -90,7 +93,7 @@ C Update the database file demo2.rrd which expects data from a single data-source, three times. First with an I<*UNKNOWN*> value then with two -normal readings. The update interval seems to be around 300 seconds. +regular readings. The update interval seems to be around 300 seconds. =head1 AUTHOR