Can a VPS show the wrong amount of memory consumed?

Question

System administration

I watched free -m memory on a tariff with 512 MB of RAM. Showed that used 512.
Raised the tariff to 1024 MB of RAM, shows that ~ 320 MB is used.

Answer 1

So the cache is .. After the tariff increase, the server was overloaded, and that's less. A couple of days later the same story will be. Check if there is a swap file. It will be useful with a small amount of RAM.

Answer 2

Can a VPS show the wrong amount of memory consumed

Easy. On OpenVZ, the allowed memory limit and the used memory are two very different things. habrahabr.ru/post/53236
But yours is trite - you just don't understand what used means in the free output.

Answer 3

[email protected]:~$ free -m
             total       used       free     shared    buffers     cached
Mem:          7687       7474        212          0        304       1104

The memory actually consumed by applications is used minus cached minus buffers
That is, in this case, 6066, if I'm not mistaken in the calculator.
In order not to think - open htop and look at ram in it - the number to the right of the ram bar will show the memory actually consumed by applications.
buffers is the data that should be written to disk but not yet written.
cached is the disk cache for reading.
In general, linux always tries to take up all the available memory.