Recently rebuilt my QNAP TS-251+ (8GB version) with 2 x 2TB SanDisk Ultra 3D SSDs. Which runs RoonServer, PLEX and AssetUPNP.
Installed one disk at a time ... now both disks operate as two independent drives and locations:
Inserted and setup Disk 1 as a 'static volume' called: 'Disk 1 - Media' (system).
All apps are installed here including, RoonServer, Roon database, PLEX, and Asset UPNP.
2 shared folder created called: 'Film' and 'Photos'. These are accessible via WiFi as secured and mapped drives on my laptop to allow 'drag and drop'.
Then once built and the above completed:
Inserted and setup Disk 2 as a 'static volume' called: 'Disk 2 - Music'.
This is used purely for FLAC file location and storage, no apps or databases installed.
1 shared folder created called: 'Music'. This is accessible via WiFi as a secured mapped drive on my laptop to allow 'drag and drop'.
This is a really clean and easy way to build a flexible media server that capable of doing more than just roon only.
Connections from the NAS to the system are:
Ethernet out to the amps builtin streamer for Asset UPNP via a switch.
USB out to the amps build in DAC for roonserver/player direct from NAS.
The NAS sits 1m away from the amp and is totally silent, even though it does have a fan.
Granted when roon was building its database the fan ramped up from 1000rpm to 1800rpm and was audible for a few mins/occasions, but once built it slows down again.
I see the fan as a 'bonus protection layer'.. my amp has 3 silent fans anyhow.
I use 2 x (identical) Toshiba 2TB USB HDD's as a 'hard back-up' for each drive. These are kept in a safe place away from the system.