banshee/linux-collection/linux/ssh/memory

Memory of a Linux, by SSH

Returns the physical memory, the memory available as the kernel counts it, the used memory and its share. Swap is the linux/ssh/swap collector.

Versions

Generic: /proc/meminfo is written by the kernel the same way on Alpine, Debian and Fedora. A kernel older than 3.14, without MemAvailable, stops the collector misconfigured rather than guess.

How it works

The collector runs cat /proc/meminfo and reads MemTotal and MemAvailable.

MemAvailable is the kernel's estimate of what can be given to a program without swapping: free memory plus the caches and buffers that can be dropped. Used memory is MemTotal − MemAvailable: caches do not count as used.
Nothing is written on the target.

Prerequisites

an SSH account for monitoring, without write rights;
the fingerprint of the server's host key, set in protocol:ssh:fingerprint (not needed when the Security settings trust the first SSH fingerprint presented).

Outputs

Name	Label	Unit	Per instance
`total`	Physical memory	MiB	no
`used`	Used memory	MiB	no
`available`	Available memory	MiB	no
`used-percent`	Used memory	%	no

Watches

Name	Title	Kind	Defaults	Checked by default
`memory-high`	Memory saturated	above a threshold, on `used-percent`	warning above 90 %, critical above 95 %, for 3 runs	yes
`available`	Little memory available	below a threshold, on `available`	critical below 512 MiB; no warning	no

Limits

In a container without lxcfs, /proc/meminfo shows the host's memory, not the container's limit.