Free Memory Percentage - Will this trigger do it?

[bignose]

I want to make a rather generic trigger that flips when my available memory is less than 80%.

So I did this:

({Template_Linux:vm.memory.size[free].last(0)}/{Template_Linux:vm.memory.size[total].last(0)})*100<20

Did I do this right?

[Bennie]

You can use vm.memory.size[pfree]

Gives back free memory in percentage, easier to create a trigger on that one:
{Template_Linux:vm.memory.size[pfree].last(0)}<20

[mitul.nfdil]

Can you please explain this -> {Template_Linux:vm.memory.size[pfree].last(0)}<20
I mean what does every term means in this expression?

[alixen]

Hi Bennie and Bignose,

Your formula are both correct but chances are that free memory will always be below 20% on your Linux servers since Linux tends to use all "unused" memory as a disk cache.

If you want to be sure that you are really running out of memory, you should either add "cached" and "buffer" memory to "free" or (this is my preferred solution) check swap usage instead of memory usage.

Regards,
Alixen

[huangyingja]

Just FYI ~
Plz check the attachment picture.
It works now !