centos man page for rrdresize

RRDRESIZE(1)							      rrdtool							      RRDRESIZE(1)

NAME
       rrdresize - alters the size of an RRA and creates a new .rrd file

SYNOPSIS
       rrdtool resize filename rra-num	GROW|SHRINK rows

DESCRIPTION
       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.

NOTES
       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.

AUTHOR
       Alex van den Bogaerdt <alex@vandenbogaerdt.nl>

1.4.8								    2013-05-23							      RRDRESIZE(1)