How to reduce Mongodb appetites in ram?

Question

MongoDB

The server is up for 2438455 seconds
Mongodb version is 3.2.10
Process id is 16325
Process name is mongod
2 Collections 26593714 Objects
15634.11 MBs Data Size 5685.72 MBs Storage Size
5 Indexes 677.25 MBs Index Size
0.00 MBs File Size 0 Extents
by htop shows that it ate 15GB

Answer 1

It's best to ditch MongoDB, that's the point of it.

Answer 2

htop shows that he ate 15GB

You can't tell from htop how much he ate. It can be calculated from /proc//memory...
Rather, the files are cached - unused memory is being used, this is normal.
What does free -m show?

Answer 3

add to the config:
storage.wiredTiger.engineConfig.cacheSizeGB: 2 (or how much you allow him)
By default, there is 60% of RAM, which he eats over time.