How do I create useful memory triggers?

[dennisj]

I'm trying to create a trigger that is supposed to fire when a system runs out of memory but I'm not sure how to accomplish this. The default linux template contains such a trigger but that is not very useful because it doesn't take cache memory into account i.e. the free memory might reach zero and the trigger will fire even though there's 2G cache memory left.
Is there a way to combine items in triggers and e.g. say "fire if (free + cache + buffer) < 10000"?

[zabbix_zen]

You can pretty much get any Trigger calculation you want.
For that specific case,

({hostA:vm.memory.size[free].last(0)} + {hostA:vm.memory.size[cached] + {hostA:vm.memory.size[buffers])<10000


Or you can do it at item level,
search for 'Calculated Items' in the Manual

[harmonica]

{hostA:vm.memory.size[available])<10000

[alixen]

Hi,

We have taken a different approach.
We don't have any trigger based on free memory on Linux systems since they always try to use as much memory as possible.
We have defined triggers on swap usage and we find them very useful.

Regards,
Alixen

[dennisj]

You can pretty much get any Trigger calculation you want.
For that specific case,

({hostA:vm.memory.size[free].last(0)} + {hostA:vm.memory.size[cached] + {hostA:vm.memory.size[buffers])<10000


Or you can do it at item level,
search for 'Calculated Items' in the Manual

I successfully set up a calculated item. Thanks for the pointer!

[dennisj]

{hostA:vm.memory.size[available])<10000

According to this page that key doesn't exist:
http://www.zabbix.com/documentation/...ed_by_platform

[harmonica]

According to this page that key doesn't exist:
http://www.zabbix.com/documentation/...ed_by_platform

The key is correct.

[dennisj]

Filed a bug against the documentation here:

"The keys "vm.memory.size[pfree]" and "vm.memory.size[available]" are not documented"

https://support.zabbix.com/browse/ZBX-2307