Producers
- synology.com (preferred)
- qnap
- drobo (good, but too expensive)
They all offer some kind of flexible disk mirroring with non-identical disks resp. disk sizes.
Main criteria:
- mini tower, not rack
- …
My colleague’s good advice: Use Samsung disks!
Apparently “they all” have hardware compatibility lists, i.e. they don’t work with every disk.
I think, it will be this one: Synology Diskstation DS213+ NAS System 6TB (2x 3TB WD Red für NAS WD30EFRX). This is the one I got today.