Why is the consumption of RAM on the server increasing?

Question

RAM

There are 2 Ubuntu 16.04 with PHP-7.0, MySQL, PhpMyAdmin installed. On one ngnix, on the other apache2.
In the server load statistics, I see a gradual increase in memory consumption, and after a reboot, the load decreases.

I searched the net and, apart from statements that reboot is not needed on * nix servers , I did not find an answer to this question

Answer 1

run the free -m command.
Part of the memory is given for buffers and cache, if necessary, this memory will be issued at the request of the application.
In general, it is normal when there is about 15-20% free memory left .... maybe even less..
And about rebooting ...
[[email protected] ~]# uptime
09:16:08 up 1257 days, 22:45, 1 user, load average: 7.07, 6.43, 5.72
and why overload it....

Answer 2

RAM is needed to be used, why don't you like it?