If you run a lot of Linux systems, you might have noticed that they sometimes run slowly. If your systems are slow, that means your business could suffer, so you’ll want to find out why that is happening. Let’s say you decide to first check whether you have enough memory.
Free your mind
To check your memory on Linux, use the
free command. For example:
$ free -h total used free shared buff/cache available Mem: 926M 41M 542M 6.2M 341M 814M Swap: 99M 512K 99M
-h to make the output easier to read as a
human. According to the
available column, this system has 926 MB of memory, and 814 MB free. There’s plenty of memory available!
Free your old mind
If you are running an older system, be careful! There is no
available column, which might give you the impression that you have far less memory than you think. For example:
$ free -m total used free shared buffers cached Mem: 995 821 173 0 31 668 -/+ buffers/cache: 122 873 Swap: 1023 0 1023
Notice we had to use
megabytes, instead of
-h. Also notice that
free shows 173 MB on the first line, and 873 MB on the second line. The second line is the same as
available on newer systems. Thus, this system also has plenty of memory available!