On the left, my first 'proper' rack. Specs - Router - Cisco 887VAMW Unmanaged Netgear switch Two laptops (Asus X550Jk and HP Pavillion DV6) both running proxmox which has Pihole, Nextcloud, Bitwarden, Roundcube webmail and Nginx proxy server. Both laptops have their batteries removed to avoid them swelling too much. A Phillips Hue hub and TP Link Deco M5 router at the bottom. On top is a mishmash of leftover parts which is currently running TrueNas and Jellyfin. This is going to eventually replace the D-Link sharecentre hidden in the back. Specs of the pc on top - CPU - AMD FX 6100 (An older model but still has it where it counts) RAM - 8Gb DDR3 (Plans to upgrade it to 16Gb at some point) GPU - GeForce GT 710 (Honestly just there so I can get an ouput) Storage 2x 1Tb WD Red drives (With plans to add 2x 4tb WD Red Drives from Sharecentre)
On the right is the mess that is yet to be fixed. On the top shelf is a selection of cisco switches and routers which are being used as a lab for me doing my CCNA (Hence the mess there). On the bottom is the same Lack rack as on the left just with slightly different components. Specs - Router - Cisco 887VAMW Switch - Some managed Netgear switch from 2004 (It's on it's way out and will be replaced very soon) First Dell Poweredge R420, with two Xeon E5-2403, 80Gb RAM and about 3Tb of Storage. This is my new Proxmox host. Second Dell Poweredge R420 with a single Xeon E5-2403, 64Gb RAM and 7Tb Storage running TrueNas. On top is an old AMD Bulldozer machine I only use for ripping and encoding DVD files.
Honestly, throw a couple services running on ubuntu servers on the proxmox machine. It's not the same as book learning, but it does help a lot with the basics and patchy knowledge I found. Not saying I'm an expert or anything, but I do know a lot more about managing Linux servers now than I did 5 years ago from running 15 of them on Proxmox