One of my hobbies that kind of escalated during the pandemic is collecting and running rackmount servers. And stuff from around 2010 turned out to be relatively affordable, with some pretty weird processor architectures floating around. A small review of the stack:
Apple Xserve
The latest addition to the stack. This dual Xeon based machine looks very nice, but greatly suffers from not invented here syndrome. It has the Apple variant of EFI and HDD brackets that are the most complicated I've seen yet. To get an os on there and administer it pretty much required another Apple machine. It runs OSX lion, has decent performance, and therefore it got a spot in the stack.
Sun / oracle Sun Fire X4170
A fairly conventional machine from right around the time Sun Microsystems was bought by oracle. It has dual Xeon processors and is the fastest in the rack. I put in 4x 5TB drives and a 1TB SSD (the pink brakets), increased the ram to 144GB, a 10Gbit NIC, and a 40Gbit infiniband card. It's a bit loud, so it spends most of it's time off, but it is a great machine for experiments and running infra at lan parties.
Sun / oracle Sparc Enterprise T5120
A machine from the same era as the other Sun, but this one is running a single Sparc T2 processor. The idea of this processor was nice, where it interleaved processing so you get 32 threads from 4 cores. Except that if you have something single threaded, performance drops below that of a raspberry pi zero. It does run the latest Debian and I like the serial based management interface.
HP DL360 Gen7
The machine replaced by the X4170. It was my first server and I got a decent amount of use out of it running VM's and doing stuff with pixelflut at lan parties. It's starting to show it's age, with some thinner steel parts starting to rust. The weird quirk of this machine is that the fans go to 100% if you insert sata HDDs, so it's running 4 SSD's
IBM Power720
It's a 4u beast from IBM powered by a Power7 processor. All if it feels more like a mainframe than a x86 based server. Things like memory and power supply modules are on separate pcbs, with plastic handles to lock them in place. You can get expansion modules to attach a whole bunch of disks, or I/O in a separate chassis. The management interface is very extensive and feels like it could also work with a teletype printer.
It did take me a week to get an OS on this machine. First I had to find out how to factory reset the management interface to get into the boot menu. Then I tried to install several linux and BSD variants from USB, without success. I had a breakthrough with AIX, which at least told be the machine worked. In a moment of desperation I burned a Debian ISO to a CD and that worked. So now it's running Debian 11.
HP DL360 Gen6
Another DL360, with this one being configured very minimally. It's the most silent of the bunch and therefore it is the only one permanently on. It runs my RSS reader and Grafana monitoring stack.