I want to separate my files from web server for performance

I have web server for run my php files.But I still storage and upload my files in web server(192.168.2.22).I want to upload my files to 192.168.2.15(Free Nas) for performance.But I need answer some question and find best way. 1.Should I share a directory in 192.168.2.15(Free NAS) and mount this directory in my web server.? 2.Should I use ftp protocol for upload (Free NAS).? 3.Should I use cURL method for upload and get files?