Provided by: rrdtool_1.4.7-2ubuntu5_amd64
rrdresize - alters the size of an RRA and creates a new .rrd file
rrdtool resize filename rra-num GROW|SHRINK rows
The resize function is used to modify the number of rows in an RRA. filename the name of the RRD you want to alter. rra-num the RRA you want to alter. You can find the number using rrdtool info. GROW used if you want to add extra rows to an RRA. The extra rows will be inserted as the rows that are oldest. SHRINK used if you want to remove rows from an RRA. The rows that will be removed are the oldest rows. rows the number of rows you want to add or remove.
The new .rrd file, with the modified RRAs, is written to the file resize.rrd in the current directory. The original .rrd file is not modified. It is possible to abuse this tool and get strange results by first removing some rows and then reinserting the same amount (effectively clearing them to be Unknown). You may thus end up with unknown data in one RRA while at the same timestamp this data is available in another RRA.
Alex van den Bogaerdt <email@example.com>