There is no free RAM on the server with Bitrix - is this normal?

Question

1C-Bitrix

Available :
VPS server from REG.ru SSD-VPS-3 (OpenVZ, SSD: 25 GB, CPU: 2x2000 MHz, RAM: 2048 MB).
CentOS 7 is installed on it and Bitrix is ​​installed on top of it: Web Environment (version 7.2.2)
Problem :
In the Scaling Control Panel, I see indicators indicating that all RAM is occupied (0 MB free).
In the terminal, when you use the "top" command, you can see that the systemd process eats up almost all the memory.
Periodically, backups stop forming on the site, MySQl crashes / crashes. Despite the fact that recently everything was put clean.
Bitrix technical support official answer :

The use of RAM is not a problem, on the contrary, it indicates the good performance of the cache.
If there are no out-of-memory errors, then everything is in order.

Please tell me how "normal" this scenario is and what measures should be taken?
UPD: I changed the server to vscale.io (KVM, SSD: 60 GB, CPU: 2x2300 MHz, RAM: 4096 MB), I switched on a 4 GB swap, but the memory is still almost always full:

Answer 1

The question is how do you define free memory. If caches are included in the occupied memory and zero is free, then this is good.
And if you consider caches free, and zero free, then everything is bad. That's how I feel about monitoring.
Type free -m in the console and give the result.

Answer 2

no, it's not normal, but you need to look at what she's doing, maybe memkesh eats all the memory.
maybe a sequel, in general, you need to watch from the console what is going on there