ulimit or files-max?

[Alex]

Hi, what is the current way to increase the number of available open files?
This is for a mariadb database server I'm trying to configure based on
instructions from the database developer to increase the total number of
files to 50000. I've added the following to /etc/security/limits.conf and
rebooted:

root            -       nofile          50000

ulimit -n as root now shows:
# ulimit -n
50000

Can this value also be set by using sysctl and setting fs.file-max to 50000?
# sysctl -a|grep file
fs.file-max = 50000
fs.file-nr = 6864       0       50000
fs.xfs.filestream_centisecs = 3000

Which is the correct way? Also, does fs.file-nr mean there are currently
6864 open files on the system?