old-way
https://easyengine.io/tutorials/linux/increase-open-files-limit/
https://askubuntu.com/questions/162229/how-do-i-increase-the-open-files-limit-for-a-non-root-user
https://serverfault.com/questions/20387/too-many-open-files-on-debian

!!! limits.conf does not work at manjaro !!!
You can add this in /etc/security/limits.conf

root soft nofile 100000
root hard nofile 100000

save then reboot.

systemd-way
https://fredrikaverpil.github.io/2016/04/27/systemd-and-resource-limits/
https://wiki.archlinux.org/index.php/Limits.conf

/etc/systemd/system.conf

#DefaultLimitNOFILE=


System-Wide Limit

!!! absent at manjaro !!!
/etc/sysctl.conf 
...
fs.file-max = 2097152

sysctl -p

Above will increase “total” number of files that can remain open system-wide.


Verify New Limits

Use following command to see max limit of file descriptors:

cat /proc/sys/fs/file-max

Hard Limit

ulimit
    -a
        ?
    -Hn
        hard limit
    -Sn
        soft limit