I wonder how they do this. Are the drives even SAS/NVMe/some standard interface, or are they fully proprietary? What "logic" is being done on the controller/backplane vs. in the drive itself?

If they have moved significant amounts of logic such as bad block management and such to the backplane, it's an interesting further example of "full circle" in the tech industry. (e.g. we started out using terminals, then went to locally running software, and now we're slowly moving back towards hosted software via web apps/VDI.) I see no practical reason to do this other than (theoretically) reducing manufacturing costs and (definitely) pushing vendor lock-in. Not like we haven't seen that sorta stuff done with e.g. NetApp messing with firmware on drives though.

However if they just mean that the 29TB disks are SAS drives and the enclosure firmware implements some sort of proprietary filesystem and that the disks are only officially supported in their enclosure, but the disk could operate on its own as just a big 29TB drive, we could in theory get these drives used and stick them in any NAS running ZFS or similar. (I'm reminded of how they originally pitched the small 16/32GB Optanes as "accelerators" and for a short time people weren't sure if you could just use them as tiny NVMe SSDs - turned out you could. I have a Linux box that uses an Optane 16GB as a boot/log/cache drive and it works beautifully. Similarly those 800GB "Oracle accelerators" are just SSDs, one of them is my VM store in my VM box.)

/storage.

It's not the top level directory. I do have some other stuff on /data. 😂