As for backup, you can also buy a e.g. Lenovo M920q minipc, buy a pci-e riser, buy a dual port ethernet card, set up Proxmox, set up an pfSense (or OpenWRT, or OPNsense) VM inside, pass-through the ethernet card directly to the VM. The VM is very backupable, since you just copy the VM state and save it somewhere. This would only work for the router though, since the AP’s that’d be running OpenWRT wouldn’t be VMs. This is at the cost of having to deal with an additional layer for the VMs.
I guess the problem you’re asking about in regards in regards to cross-device portability of a backed up config is valid. If you had a four ETH port router, backed up the config, and then uploaded it on a two ETH port router, you’d run into trouble, but I have no experience here.
You can also install OpenWrt on some switches these days (PoE also reportedly works with realtek-poe module):
- https://forum.openwrt.org/t/support-for-rtl838x-based-managed-switches/57875/
- https://openwrt.org/toh/views/toh_standard_all?dataflt[Device+Type*~]=Switch
That way you’d have a fully open OpenWRT-only network lab, so you’d always be working with the same system.
UPDATE: Turned out that the culprit of the downtime was my switch - the D-Link DGS-1210-10P rev. B1.
The way the management web interface of the switch works is pretty unintuitive. Namely, if you change some settings in the web interface and hit save in one of the sections, the settings are saved in the volatile memory of the switch. This basically means that the settings are only saved in RAM, which is cleared on power loss. To save the settings into non-volatile memory which persists on reboots, you need to find the “Save” section at the top of the UI. This is described here: https://networkengineering.stackexchange.com/questions/20158/dlink-switch-loses-configuration-on-power-off
So basically, my problem was that the settings weren’t commied to nonvolatile memory and on a short 1 minute power loss the switch restarted.
I got an UPS anyway now, SMT750RMI2U