Linux memory management

I think that is a common question for every Linux user soon or later in their career of desktop or server administrator “Why Linux uses all my Ram while not doing much ?”. To this one today I’ve add another question that I’m sure is common for many Linux system administrator “Why the command free show swap used and I’ve so much free Ram ?”, so from my study of today on SwapCached i present to you some useful, or at least i hope so, information on the management of memory in a Linux system.

Linux has this basic rule: a page of free RAM is wasted RAM. RAM is used for a lot more than just user application data. It also stores data for the kernel itself and, most importantly, can mirror data stored on the disk for super-fast access, this is reported usually as “buffers/cache”, “disk cache” or “cached” by top. Cached memory is essentially free, in that it can be replaced quickly if a running (or newly starting) program needs the memory.

Keeping the cache means that if something needs the same data again, there’s a good chance it will still be in the cache in memory.

So as first thing in your system you can use the command free to get a first idea of how is going the use of your RAM.

This is the output on my old laptop with Xubuntu:

Läs hela artikeln.