A drawback of the Pi 4 is that if you want to do RAID with USB hard drives, I found that you need a separate powered USB hub for each disk. That's (A) to give them enough power (although I used spinning disks, it may or may not be necessary for SSDs), and (B) I found that when I had them on the same hub or on the Pi directly, when one disk went down, it would lead to the other disk becoming inaccessible as well. It seems with separate hubs, that's not an issue. (Don't ask me about the technical details why that might be so, if you know more and can explain that I'm wrong, go for it, it was simply the result of my experiments (with an n of 2 or 3 or so), and does make sense in that there's more electronics between the drives to shield, and it's indirectly addressed so maybe the kernel is less confused, whatever.)<p>My current setup with two hubs has been working reliably so far, but in spite of it all being USB3 it's still not that fast (about 100MB/s serially top--I'd hope that the 3.25'' disk drives (new 4 TB drives, WD Elements 2620 and Seagate Basic STJL4000400) could do more, but maybe I'm wrong). So for my next tiny servers / appliances, I want to try either of the following instead, which have SATA which should be more reliable and faster:<p><a href="https://www.pcengines.ch/newshop.php?c=48881" rel="nofollow">https://www.pcengines.ch/newshop.php?c=48881</a><p><a href="https://www.olimex.com/Products/OLinuXino/Home-Server/LIME2-SERVER-NO-HDD/open-source-hardware" rel="nofollow">https://www.olimex.com/Products/OLinuXino/Home-Server/LIME2-...</a><p>Also, since Pi 4's are unobtainable here (Switzerland) currently: the Tinker Board 2 seems to be a bit faster than the Pi 4, and it has its wifi board as a plug in board, and I have been wondering if that can be replaced with a SATA interface, but haven't investigated.<p>Edit: seeing achairapart's comment, I realize that going directly from USB to SATA and then attaching disks there might have been a better option.