iXsystemsType-C HDMI Adapter - Black Metal, Tabletop Mounting, Compatible with Laptop, Tablet, Desktop

Q: Do I require a disk for the OS or is it integrated ?

Hi Nicolas, the OS is installed on an internal M.2 boot device. It is included.

Q: what is the purpose of the 2 2.5 bays?

They are for 2.5" drives (ie, laptop standard), rather than 3.5" drives (ie, desktop standard). You can use them however you'd like...I use them for doing R/W caching via SSD's, so I don't have to spend 10-100x to get full SSD speeds, when the network being used to move data to/from the server will be the speed limiting factor most of the time anyway.

Q: Does anyone know if this will be able to run truenas scale?

From my own experience, “Yes”. If your situation required “..scale” over “core”, yes. You should be able to download and eventually install.

Q: Is there a chance of getting all SSDs drives at some point?

I purchased the drives separately from the TrueNAS Mini X+. I see no reason that you could not use SSDs. You might not get the same capacity and at a higher cost, however.