Free vs. Available Memory in Linux
At times we will need to know precisely how our Linux systems use memory. This article will examine how to use the free command-line utility to view memory usage on a Linux system. In doing so, we will clearly define the difference between free vs. available memory on Linux systems.
Free memory is the amount of memory that is currently not used for anything . For this reason, especially on servers, I like to consider free memory as wasted memory. Once your applications/processes have launched and considerable uptime has passed, this number should almost always be small.
Available memory is the amount of memory that is available for allocation to new or existing processes. Available memory is then an estimation of how much memory is available for use without swapping .
The difference between free memory vs. available memory in Linux is, free memory is not in use and sits there doing nothing. While available memory is used memory that includes but is not limited to caches and buffers, that can be freed without the performance penalty of using swap space.
