Memory usage graph and top command output differs

[rober]

Hi,

I have Zabbix which monitors some Linux server.
Memory usage graph for that server reports cca 6.5 GB memory used.
At the same time top command on that server reports
KiB Mem: 7981272 total, 3374524 used, 4606748 free, 131712 buffers

There is a significant difference between 3.22 and 6.5 GB?
Where does this difference comes from?
Does top shows something else than Zabbix?
Thanks.

[ingus.vilnis]

Hi,

This depends on the actual item key used (not sure which one you are using) and on the operating system as well (various OS show different data).

You can try to do some tests and compare the results yourself.
1. https://www.zabbix.com/documentation...ry.size_params
2. http://www.binarytides.com/linux-com...-memory-usage/

Best Regards,
Ingus

[rober]

Thanks for replying, Ingus.
I'll check the links. :-)

I have also checked what item key is used for Y axis of a graph.
It is vm.memory.size[available] and it comes from a Template OS Linux.
The OS observed is CentOS.