"Deals" on used enterprise are IME dreadful unless you can get in on your own employer offloading old stuff, which requires you to a) even have an onprem setup at all and b) be friendly enough with the IT/NOC people that they give you a tip when it's going to happen. (For me b seems to happen naturally so it's really all on a).
eBay is a fools game, terrible prices. Craigslist is usually the same sellers too. Maybe some people live behind an Amazon datacenter or something, I unfortunately live in a city where the only reason we have Amazon 2-day shipping is because we're a major shipping hub. And anything that does resemble a good deal is ancient Opterons that are literally e-waste these days.
So anyway, sorry, my whole point here is that most people are actually going to be running a ton of old enterprise stuff that is actually rackmountable with good sliding rails. You're either building whiteboxes in a 4U rosewill case or you're putting stuff on rack-mountable shelves. The rosewill cases theoretically have sliding rails but they're awful, just awful. So you're either using shelf rails or literal shelves which tends to throw off efficient utilization of the U's available in the rack - shelf rails usually result in a dead U either above or below them, and shelves obviously have similar effects.
So yeah. As someone who owns a rack (4-post open rack), if you asked me, I'd say just go buy one of those big heavy duty Lowe's shelf units and ask for extra shelf inserts so you can have more, but less-tall shelves. Boom, you now have something that'll hold anything and is way better than fucking around with rack nuts and shelf rails and stuff.
10-15 years ago the deals were real. I picked up a lot of off-lease and/or used stuff on ebay really cheap. As more and more companies move to cloud, and as more people get into homelabs, prices on decent gear have gone up. I was starting to think the good times were over in 2018 and in 2020 I stopped defaulting to ebay when I saw a great lot getting broken up and sold cheap suddenly pull all their stuff and relist it at much higher prices - "the scrappers are on to us" is what I realized.
These days I've been replacing the guts of my old servers with mini-itx setups for the most part. It does what I need and lets me shove 2 or 3 nodes into a 2u case so I can keep the aesthetic of "a personal rack".
FWIW Supermicro slides work with those 4U Rosewill cases. I was pushed in that direction because my rack is just slightly narrower than 19 inches.
Honestly I don't mind wasting 1 or 2U between machines because the tops of server cases function as great "temporary" shelves.
I do agree the meme of used enterprise deals is completely overblown, unless you actually want 15+ compute nodes and are prepared to suffer power, heat, and noise for the density. Honestly I wish they made those Rosewill cases in 5U so I could put any full height cooler in there instead of being somewhat restricted.
"Deals" on used enterprise are IME dreadful unless you can get in on your own employer offloading old stuff, which requires you to a) even have an onprem setup at all and b) be friendly enough with the IT/NOC people that they give you a tip when it's going to happen. (For me b seems to happen naturally so it's really all on a).
eBay is a fools game, terrible prices. Craigslist is usually the same sellers too. Maybe some people live behind an Amazon datacenter or something, I unfortunately live in a city where the only reason we have Amazon 2-day shipping is because we're a major shipping hub. And anything that does resemble a good deal is ancient Opterons that are literally e-waste these days.
So anyway, sorry, my whole point here is that most people are actually going to be running a ton of old enterprise stuff that is actually rackmountable with good sliding rails. You're either building whiteboxes in a 4U rosewill case or you're putting stuff on rack-mountable shelves. The rosewill cases theoretically have sliding rails but they're awful, just awful. So you're either using shelf rails or literal shelves which tends to throw off efficient utilization of the U's available in the rack - shelf rails usually result in a dead U either above or below them, and shelves obviously have similar effects.
So yeah. As someone who owns a rack (4-post open rack), if you asked me, I'd say just go buy one of those big heavy duty Lowe's shelf units and ask for extra shelf inserts so you can have more, but less-tall shelves. Boom, you now have something that'll hold anything and is way better than fucking around with rack nuts and shelf rails and stuff.
Love homelabs in general, though.