Why is Library Scan Taking too Long

Hi
I am running Plex Media Server on El Capitan and the hard drive is connected over a network through Routher (netgear- dmg2200)
I've been trying to add - music, video and movie files separately for the hard drive over home network.
It's taking about 10+ hours to scan a music folder approx 80 gb data
**
Am I doing something wrong? **
I am aware that the files need to have correct meta tags but - the very reason I am using a server is to be able to - start meta tagging correctly the content I already have. So as of now only some content will have correct metatagging