Hello, thanks for your kind answer.
following the tips, I have been able finally to install it.
now I have to try it, because I am not sure the things I touched in the bios are all correct…
as a beginner in Linux, I have some difficulties to understand everything
but at least Rockstor is working perfectly and I created already a “working” structure based on a MB with J1900.
By the way, do you think the usage of a MB with J3455 will give better results?
The CPU looks better on the paper.
The RAM can be up to 16Go, and maybe the usage of one SSD to support OS can help making some cache… but this is I only guess because I don’t know exactly if the system is able to do so…