[rrd-users] Scaling the y-axsis

[jan-terje.larsen at telenor.com]

Hello,

I'm trying to get better control over the upper and lower limits of graphs instead of relying on autoscale. 
My data will be in the range of 0 - 20000ns. I never want the y-axis to be less than 30ns top to bottom.

As far as I can understand the rrdtool graph function does not support this directly. So my approach now is to get the max and min values in the selected time window and add 15 to max and subtract 15 from min, then set upper-limit and lower-limit accordingly.

Does this make sense ?

I've been partially successfull using graphv returnvalues value_min and value_max. But these are not always reporting the real max and min of my data. What are they supposed to reflect ?

Your input would be appreciated, I'm a bit lost now ...

Best Regards,
Jan-Terje Larsen