On Thu, Oct 29, 2020 at 11:08:20AM -0600, Theo de Raadt wrote: > Aleksander De <[email protected]> wrote: > > > Are there any downsides or potential issues which may happen when > > extending boundaries for OpenBSD partition on >2TB disk while using > > MBR for booting it at the same time? I need MBR otherwise the machine > > will not boot. BIOS/RAID controller does not support UEFI. > > The BIOS will use the MBR to identify the bootable partition. Then > it will load the PBR sector as code, jump to it, and then load further > bootblock code, and kernel after that. It is important to not have the > root partition in an earlier part of the disk (I'm being intentionally > vague). > > But our bootcode does not care about the partition limits. What happens > is disklabel looks at the MBR partition limits -- when non-MBR > partitions (ie disklabel partitions) are being created, usually during > install. Beyond that, the MBR size is never looked at again. > > Where MBR partition limits can matter, is if you go back to disklabel > again manually to create partitions. It's splitting the disk up. If > you are not careful, you could create overlaps. This mostly happens to > people putting multiple operating systems on a machine. Those people > need to be careful. Everyone else can ignore this.
Thank you very much Otto and Theo. -- Aleksander
