Re: BIOS/MBR drive enumeration order, FreeBSD dev nodes, GELI ZFS root, and ZFS boot

On 6/21/22 14:58, Polytropon wrote:
> Oops, sorry, sent from wrong account, hope that ome comes through.
> Stupid fat fingers! ;-)
> 
> 
> On Mon, 20 Jun 2022 23:24:44 -0700, David Christensen wrote:
>> I have several older machines in my SOHO network.  BIOS/MBR is the
>> lowest common denominator, so that is what I use.  AIUI MBR does not
>> support partition labels, only GPT.
> 
> You could use labels even before GPT existed. :-)
> 
> Check the Handbook for three (!) possibilities: glabel, tunefs, UFSID.
> All of them work fine with FreeBSD partitions inside slices a. k. a.
> "DOS primary partitions".
> 
> 
> 
>> I seem to recall that it is possible to slice/ partition the boot/ root
>> drive with a hybrid MBR/ GPT scheme such that BIOS thinks the drive is
>> MBR but the FreeBSD boot loader switches to GPT at some point (?).
> 
> I don't remember that specific setup, but it sounds entirely possible.
> The key is that the BIOS or EFI needs to hand action over to something
> it can recognize, e. g., a GPT partition with the FreeBSD boot loader.
>  From there on, anything is possible, as the boot loader can use all
> three things possible: GPT partitions, BSD partitions inside slices,
> BSD partitions on the device (without slice, called "dedicated").
> On top of that, the use of labels (one kind or another) is still
> possible.
> 
> Still... as this looks like a nonstandard approach, I assume you
> will have to construct the "boot chain" manually with the common
> tools, like gpart, maybe fdisk & bsdlabel, boot0cfg, and newfs.
> Needless to say, you can easily script those. ;-)


Thank you for the reply.


I will see if I can find a solution.


David