CI3 Multiple apps one source optimal performance

Hey Guys,

I've been struggling with this question for a while now. I've created an app in CI3, at first i had 1 client that used it so no problem there. Now after a few years i have 20+ clients using this app.

At start i placed the full app package (system / application) folder in a subdomain of my hosting (1 server), so everyone has their own instance of the app. But to update / maintain all those seperate versions is a nightmare. Also: Each app also relies on their own database.

So i'm thinking about moving the system and application folders of the app to a central location on the server (outside www folder), and each subdomain will have an index file and some custom config files. And all apps will rely on that one central location to function.

My main concern is that this will lead to a lower performance since they all rely on that one source-location. Will it increase performance if i create multiple source "hubs"? So that for example 10 apps run of one source, and so for each 10 apps create a different hub?

All of this is done on one server with subdomains. (for the moment)

Looking forward hearing your opinion on this matter. 

Best regards,
Bart