Absolutely. Many small businesses are powered by two-generations-ago rack mounted appliances and blades.
It's often the most cost effective way to get redundant and A+A power supplies in servers that you need to protect beyond simple UPS methods.
Source: Loving the 2U and 4U blades with 2017-2020 era EPYC and Xeon processors with dirt-cheap Tesla P40 24GB VRAM GPUs in them for inference and all sorts of compute loads.
There’s no such thing as a 2u blade, blade servers are a different thing than #u “pizza boxes”. Generally speaking they’re chassis mounted servers with shared power and I/O through mezzanine cards/backplanes(yes there are blades without shared power and/or I/O, but they’re the exception).
Blade enclosures are different than blade servers. Small servers like that are also very unlikely to be loaded up with high-watt GPUs for inference or training workloads.
The number of Us is about height, not width or mounting hardware - and all the blades I've worked with were 2U high for a "9-inch rack" that just happened to be mounted inside a larger rack.
I mean, it’s a free country you can do whatever you want, but you should be aware that you are not using that term the way anyone else uses it.
Rack Us absolutely refer to a form factor not just a z-height. It would make no sense to refer to something in # of Us unless you either want to then mount it in a rack, or be deliberately annoying.
> but you should be aware that you are not using that term the way anyone else uses it.
Most people (including, typically, the companies actually manufacturing and selling blades and enclosures) would also in this context reasonably infer "2U or 4U blade" to be referring to a (partially-or-fully-)filled enclosure, rather than pedantically assume that someone (who is implied to own and use such a server) doesn't know the difference between a blade and a pizza box - but given that we've already deviated from using terms the way anyone else uses them, what's one more deviation, right? :)
Of course they wouldn’t, blades are blades and enclosures are enclosures. It’s really not that difficult of a concept.
The entire point of blades is that they’re modular and a chassis can be filled with many different kinds of blades. Calling an enclosure a blade would be like calling a tire a car.
Source: I’ve specd out and ordered literally thousands of blade servers and hundreds of enclosures from every major vendor.
Edit: an even better simile would have been people who call a whole desktop computer a cpu.
Double-edged sword. Higher prices brand new, but vastly cheaper used if you chase companies' deprecation cycles.