Recently I configured some passive checks in Zabbix. Now, I saw that some checks failed for some periods of time, but this is not clear when looking at the chart. It seems that the value was stable for the last week but in real performance went down and nobody recognized it.
Is there a way to send NULL to Zabbix to indicate that fetching of the data failed? And to add a trigger for this case? I'm currently using the command line tool
zabbix_sender to upload the results, but can change to an alternative.
In contrast, munin stops graphing 10 minutes after receiving the last value and the missing values are also not influencing the calculation of the average value.
Here you can see how the 'missing data' is displayed:
in the chart (I marked the 'missing data'):
in the 'Last data' table (the line is grayed out, but the value 'last check' shows almost the current time)
Btw: the same problems is in the
icmppingsec check which just returns 0 in case of an error. Not very helpful for graphing but at least this avoids false negatives.