What's a good use for a sff server? I've got a couple and don't know what to do with them. Both are 24 port. One, a 2u Quanta is loaded with 24 900GB drives. I'm using it for backup duty at present. It's a sweet box and fully loaded including SAS3, 10G network plus 2 1G and E5 26xxv3 /4 compatibility.. The other is a Supermicro SC216 also a 24 port. It's loaded with 24 450GB drives and is doing nothing but taking up space at present.
An all SSD NAS? For a time I used a SC119 that way. The rack is in my home office, so I thought to have just one low power "always on" box to keep the noise and heat down. Not a lot of capacity, so it had just the frequently accessed and temporary stuff, but very quiet and low idle power compared to the boxes with a lot of spinners that I then turned on as needed.
I use a system in a SC219 for tinkering with software on bare metal. I think some stuff, like hypervisors, is easier to test/play with that way. I had a stack of 1TB 5400 RPM 2.5" drives left over from laptop/desktop upgrades for family and friends, so it was cheap to deploy. Since its not "production" the slow speed isn't a huge issue. When I switched back to TrueNAS for my main NAS, after 5 or so years away, I used it to make sure I knew what I was doing before I tried to use TrueNAS again out in the wild.