On 2018/02/01 14:34, ti...@openmailbox.org wrote: > Hi Stuart, thanks a lot for responding - > > The most relevant followup question is probably the one about > why not using boot.conf would work out, at the bottom. > > > On 2018-02-01, ti...@openmailbox.org <ti...@openmailbox.org> wrote: > >> Hi, so, this question sprung from the previous email however it's a big > >> one and so deserves to be addressed separately: > >> > >> If a machine's BIOS does not support booting from a particular boot > >> medium where OpenBSD is installed, e.g. my BIOS does maybe not > >> supporting booting from PCIe NVME SSD:s, but it does support booting > >> from USB memory sticks. > >> > >> For such situations, how can I create an OpenBSD USB stick boot disk, > >> that continues the OpenBSD boot process for me but from the PCIe NVME > >> SSD-stored crypto softraid? > >> > >> This could be done either by > >> > >> * The OpenBSD kernel being stored on the USB stick, loading from it, > >> and then using the PCIe NVME SSD as both root disk, swap disk, and > >> dump disk, or, > > > > I think this should be possible with a custom kernel to set the > > devices. Updates will be annoying and it will be tough to get KARL > > to work nicely. > > Wait what does KARL mean here?
The random kernel re-linking done before first boot and after each boot (also used as the basis for syspatch kernel updates). > And what's the kernel compile time setting, would this be a patch or > is there some define somewhere? It's the "config bsd root on XXXX swap on YYYY" as you'll see in the RAMDISK kernel configs. > >> * The OpenBSD boot loader which is stored on the USB memory stick, > >> would load the OpenBSD kernel from the PCIe NVME SSD. > > > > The boot loader uses BIOS IO functions, if those can't talk to the > > NVME it's not going to work. > > I'm not sure but I think that, while some BIOS:es will not do IO with > the PCIe NVME, then, I think my BIOS (and then of course some other > peoples') actually does provide access to the NVME SSD, it's just that > it won't boot from it. > > I'd need to debug this much closer though. Do "machine diskinfo". If the NVME is listed there, you may have a chance. > >> This should be a fundamental and trivial usecase to OpenBSD, however, > >> last time I tried (then with adding a "boot" command to boot.conf per > >> http://man.openbsd.org/boot.conf ), I think it not worked out of the > >> box. > > > > It might not be very appealing but afaict the only trivial way to do > > this is to place root on the USB stick or some other device, and other > > filesystems on NVME. > > boot.conf (http://man.openbsd.org/boot.conf) specifies in three or more > places, ways to change the boot disk. > > First, do "boot hd1a:/bsd", next do "machine boot hd1a", next "set device > hd1a". > > Why would all of these three not be effective? "boot hd1a:/bsd" tries to load /bsd from BIOS device hd1. "machine boot hd1a" tries to boot the PBR (partition boot record) on the first partition of BIOS device hd1. I haven't used "set device" but I guess it would probably set a default for "boot". In all cases this is talking about a device reachable from BIOS. To access some other device (NVME, USB drive without BIOS support, etc) you'd need a driver to talk to the device, which isn't available until the kernel is running, so isn't useful for loading the kernel initially. > E.g. at completion of the OpenBSD installation do: > > echo "set device hd1a" >> /mnt/etc/boot.conf > installboot -r /mnt sd1 > > (Here, sd1 is the OpenBSD installer USB memory stick, and, when > booting from it, hd0 would be the same USB memory stick, and hd1a would > be the PCIe NVME.) > > Following up on this question in one more wider email shortly. > > Tinker
