How to change RRD data source name

To change the data source name, you need to check its current value and then issue single rrdtool command.

Check the data source (DS) name.

$ rrdtool info graph_memory.rrd  | grep ^ds | sed 's/.*\[\(.*\)\].*/\1/g' | uniq
memFree

$ rrdtool dump graph_memory.rrd | grep name
  memFree 

Change data source name from memFree to memoryFree.

$ rrdtool tune graph_memory.rrd -r memFree:memoryFree