Hi,
I found an issue running mongodb on a single server.

Server has following specs:
8 Core
16GB RAM
4GB Swap

Server has following main application:
MySQL
MongoDB

Sufficient memory is available, but Swap usage remains at 100%.

$ free -m

              total        used        free      shared  buff/cache   available
Mem:          15726       11364         157          53        4204        3932
Swap:          4095        4095           0

$ ps -ef

mongod    6453     1  0  2017 ?        1-02:38:03 /usr/bin/mongod -f /etc/mongod-config.conf
mongod    6879     1  0  2017 ?        1-00:46:58 /usr/bin/mongod -f /etc/mongod-arbiter.conf

$ cat /proc/6453/status |grep -i vmswap

VmSwap:  3346268 kB

$ cat /proc/6879/status |grep -i vmswap

VmSwap:    30456 kB

I changed the swappiness setting, but it is the same.
$ sysctl vm.swappiness

vm.swappiness = 1

Is there a way to limit mongodb's swap usage?

+ Because I do not speak English well, you may feel my question is strange.