Basically, I'm working on a REST API for my application. I was researching for server performance, and I couldn't find information on splitting a database. Would it be better to have a single file system shared through multiple servers that use MySQL (if it's possible to store it on a shared file system), or should I just upgrade my current server or store different information on different databases (for example users a-n information on database 1 and o-z on another) if it's slowing it down? If anyone has more information on increasing database performance, or something I can read through it would be very much appreciated. Thanks in advance.