Thanks a lot Nick! Is hence a big offset for the root partition a problem?
Should not also a bootable MBR partition at the end of the disk be problematic? I have seen in this list people that got problems with big root partitions. I am now tempted to test the BIOS and install OpenBSD at the very end of disk. Rod. Am Sa., 20. Sept. 2025 um 13:44 Uhr schrieb Nick Holland <[email protected]>: > > On 9/19/25 12:12, Roderick wrote: > > Are there (dis)advantages of UEFI over BIOS on an installation? > > yes -- but it's 100% a hardware issue. > Some hardware doesn't support UEFI, some hardware doesn't support BIOS/MBR. > Some hardware supports both, but one or the other is buggy. > Some hardware supports both, but one or the other works better with OpenBSD. > > yes, I've seen HW that was sold as a linux device (HP thin clients) that > /required/ using MBR/BIOS for Linux, but /required/ EFI to work with OpenBSD > properly. > > > I need the computer only for desktop with OpenBSD, no 24h server. > > no impact on the decision process there. > > By the way, are there restriction on the size of root / its position in the > > HDD? > On modern hardware, that pretty much says "doing it wrong". > Don't make a mega-root partition system. > > In all cases, the system firmware is what loads the kernel, so the system > firmware > has to understand how to access the disk where the kernel resides. IF you > had a > really old 486 that had enough memory and you put a 500GB disk on it, you > might > find that the system couldn't load the kernel beyond 8GB or even 504MB. That > sets an upper limit to the size of your root partition (other common limits > were > 2G, 32G, 40G (yeah, pretty sure that was a buggy BIOS). Of course, once the > kernel has loaded from the root partition, limitations of the system firmware > no longer apply. > > But don't make a giant root partition. > > As for disk limits, there are a number of OSs that restrict the accessible > disk > size to 2T for MBR. OpenBSD is NOT one of them. You absolutely can have as > big > a disk as you can find, and still have it be MBR. OpenBSD uses the MBR (and > EFI) > partitions just to mark off the space the OS requires; the disklabel is what > defines OS file systems for OpenBSD, and that supports very large disks. > > > Are there recommendations? > > The primary criteria I use for deciding between MBR and EFI are: > 1) what does the hardware require to run properly? > 2) What will the REPLACEMENT hardware require to run properly? > > At some point, I assume every part of the existing system will have to be > replaced, either by necessity (failure) or getting better hardware. I'd > assume > any replacement system will be better performance and probably newer than the > old system, and these days, that basically means EFI is a "safer" choice. > Yes, > today's hardware may run MBR just fine, but tomorrow's may not. MBR is very > definitely legacy now. > > Lots of words for what really boils down to a simple answer: use EFI if at all > possible. And if it isn't...reconsider your life choices. :) > > Nick. >
