Edit 'Lower Limit' doesn't change graph range

[frackers]

After a couple of months of running a weather capture display I've realised that the 'Lower Limit' on one of the graphs had a value of 0 instead of -10.

Having changed the value of 'Lower Limit', it still doesn't display values below 0 even after deleting the graph and re-creating it and adding it back to the graph tree. The capture source correctly assigns the range (-10 to 50 in this case).

Is there a way I can dump the raw data for this field from the rrd to check that negative values have been stored correctly - I can then tackle the lack of display as a separate problem then... (and perhaps other uses have an idea of why it fails?)

Thanks

[frackers]

More info...

Looks like the rrd database has got a range of 0 to 100 instead of -10 to 50. This means that all values below zero get set to "Not Available" . Is there a way of changing this without loosing 3 months of data?

Cheers

[frackers]

SOLVED (I think).

I worked out how to use rrdtool tune to change the rrd header to change the min:max limits of the entry...