Status Unknown ??? why ?

[thiago.info]

I had some problems with zabbix server yesterday, 3 servers was halted and Zabbix didn't alerted me, looking in the Events, zabbix got an UNKNOWN status in the: Server xyz is unreachable, anyone could explain me why ?

[bashman]

Seems that Zabbix doesn't alert when "unknown" values, because in this case, Zabbix cannot evaluate trigger expression. This may happen because of several reasons: server is unreachable, trigger expression cannot be evaluated, trigger expression has been recently changed.

You can vote for ZBXNEXT-341.

[James Wells]

Greetings,

I had some problems with zabbix server yesterday, 3 servers was halted and Zabbix didn't alerted me, looking in the Events, zabbix got an UNKNOWN status in the: Server xyz is unreachable, anyone could explain me why ?

This is actually what the nodata() trigger function was meant to solve. The idea is that you create a very low weight item, say system.hostname. You set the item up with 1 day of history and 0 days of trending and a delay (periodicity) of around 60 seconds. You then create a trigger on this item that looks like this;

• {<HostName>:system.hostname.nodata(180)}=1

This will fire an action any time this item goes for more than 3 minutes without an update.... Assuming that Zabbix server is running that is.

Now, the problem you will have though is any time your Zabbix server is down for more than 3 minutes, every one of these nodata alerts will fire actions.

Seems that Zabbix doesn't alert when "unknown" values, because in this case, Zabbix cannot evaluate trigger expression. This may happen because of several reasons: server is unreachable, trigger expression cannot be evaluated, trigger expression has been recently changed.

Yeah, alerting on unknown can be very very very bad. To explain why, I would need to walk you through the entire start-up process then through the entire item collection process, then through the entire trigger process. I know you don't know me from Adam, but I ask you to trust me on this, alerting on unknown is a really bad idea for Zabbix.

[bashman]

Yeah, alerting on unknown can be very very very bad. To explain why, I would need to walk you through the entire start-up process then through the entire item collection process, then through the entire trigger process. I know you don't know me from Adam, but I ask you to trust me on this, alerting on unknown is a really bad idea for Zabbix.

Makes sense, but we should know some how, when "unknown" value is set, because that could mean that Zabbix has not update an item on time, and icould mean that we don't have monitoring for that item.