i have the following probe:
name:memory
Type: function
Available: mem_size() > 0
Error: if(mem_usage() < 90, “”, “Memory used > 90%”)
Value: mem_usage()
Unit: %
Rate: none
i have a server with the memory in 95%. when i look the historial graph,i see that the memory graph is down. the same occurs in the chart graph
thanks for your help¡¡¡¡¡ 

Yeah the dude doesn’t graph when the error line is true.
The only way around this is to make two probes… one to graph and one to send notifications on error.
I hope they add a check box that allows you to graph as long as there is a value returned, and they add the last value to the bottom of the graph next to the probe name…
thank sweetdude for your answer¡¡¡