I want to achieve following.
I am plotting certain varnish related metrics. Now, my objective is to somehow retain the maximum value of any metrics which gets stored in the RRD file. I know that rrd is storing the absolute value for the last hour. So is it possible to have something (like a logtail maybe) which could keep looking for the max value in the rrd file and set the saved max to current max if the current max is greater or vice versa. Does anyone know of a way to do this? I am all set to start working on getting a solution, but thought of looking around if there is a ready made or easier solution available. Please let me know if I need to be more clear with what I am asking. Thanks.