UP Board hanging with Ubuntu Server 18.04
Mine's an original Up-Board, 2GB RAM, 32 GB eMMC. I've been running it happily with Ubilinux 3 for three years. I'm not using any special Up board features, it's just a utility server running a few network services. To be honest a Raspberry Pi would be just as good, when I bought it I specifically needed an Intel processor but that's no longer the case. But I have it and I still want to put it to good use.
The installation was getting a bit unmanageable with Ubilinux 3, some repo errors, etc, and in-place upgrade wasn't possible/supported so I decided best bet would be to move to Ubuntu Server 18.04, the rationale being better long-term support.
I installed Ubuntu 18.04.3 Server (with LVM - in hindsight I regret) and then followed instructions to replace the kernel with 'kernel 4.15.0 for UP'
Question: Given I'm not using any special features of the Up board, I'm uncertain why a specialist kernel is needed. Are there issues with the standard kernel running on Up board, or does the specialist kernel just unlock new features?
Since I reinstalled, every few hours the server will freeze (it's running headless). kern.log seems to be silent in the period that the server was 'frozen'.
One avenue I explored was to try and disable acpi via grub options, since I seem to recall I had disabled it in Ubilinux due to floods of 'hpet1: lost xxx rtc interrupts'. But that led me down another rabbit hole. The server would not even boot, failing with an error message "Failed to connect to lvmetad. Falling back to device scanning" followed by "Volume group -vg not found"... the root volume is not mountable. So I've backed off from attempts to disable acpi.
Question: Why does LVM not work when acpi is disabled?
I've just updated BIOS to in a final attempt to cure the problems, to UPC1DM15 (I was refused when trying to update to DM17... I gather that's unsupported for boards of this age?).
Any suggestions on how best to make this server stable?