how to mount synology without removing external hard drive in /mnt

Solution 1:

The mount command attaches a filesystem to a directory. You can actually attach it at any directory and you should create one for it. The /mnt directory is a frequent target of such mounts and is an empty directory created by default on most unix systems specifically for that purpose. You can mount multiple things on /mnt, even at the same time, but if you do, only the last one will be visible until you umount it to expose the previous one.

However, it is probably best to use /mnt only for temporary manual mounts (and only one at a time) and not permanent ones. I would recommend creating something like /synology or /disks/synology or something like that to make a family of directories you can target for semi-permanent mounts.

You could also either use autofs to automatically mount them on demand or add them to /etc/fstab to permanently mount them.