Hello,
for what could I use a connected USB stick?
Which data can be stored on it?
When I activate the “storing on disk” in Graphing/Interface Rules or Ressource Rules, does the router save the data automatically on the stick instead of the internal memory?
If someone uses the Web Proxy can this data be stored on the USB stick?
You can store Web proxy data there, logs or use it as ftp server storage. Do not expect any interesting performance as usb operation is done very slowly.
Ok thx.
The RB3011 will has a USB 3.0 port. The external memory also should be used for the “graphing data”.
Webproxy and FTP-server are a nice feature but there are more performance solutions available and should not be integrated on a router. 
It depends. Just usb3 port doesn’t ensure fast operation when slow drivers will be used further in ros and port operation will be driven by cpu in software mode. I am also interested in 3011 so I am waiting for how it will be.
The rest is question of who needs what.
You are right - I am also curious for RB3011. 