If you run free -h and check Free Memory this should be correct. Your thinking of Available memory which is not reported in LibreNMS as i don’t think it’s available over snmp, you can test yourself against some of the oids http://www.net-snmp.org/docs/mibs/ucdavis.html
I have the same issue. After reboot of LibreNMS server (Ubuntu 18.04), the cached memory increases up to use 90% and more. After some hours or days, the system slowdown and finally hangs. To avoid this, I’m currently rebooting server every 24 h.
Not yet found a solution for this issue. I cannot understand if the tuning must be done on LibreNMS or the Linux machine itself.
Same issues for anybody?
So I’ve done some testing on Ubuntu 18.04 and 16.04 both of my test machines did not give this memory error
Which is weird so I taught maybe it is the way the device is discovered and polled for the first time I deleted the host with the memory problem and re-added his and got the same error did this bout 4 time with no luck.
and after all this testing I was only left with sadness!!