8.2-RELEASE - gmirror and gpart issue. Metadata overlap?

Johan Hendriks Johan at double-l.nl
Mon Feb 28 09:11:03 UTC 2011

On 26.02.2011 15:26, Marin Atanasov Nikolov wrote:
>> After a reboot I get this right before the FreeBSD bootloader starts:
>> gptboot: invalid GPT backup header
>> I suppose this error simply means that gpart can't find it's backup 
>> header, because gmirror and gpart both are using the last sectors for

>> a provider to write it's metadata.

>This message is from gptboot. Loader does not know about your software
mirror and it just checks GPT headers in the second and last LBA.
>As i see now, there is inconsistency in the behavior between gptboot

>gptboot does reading of GPT backup header from the last LBA, but
GEOM_PART_GPT from the alternate LBA which is not equal to last LBA in
your case.

>> Which would mean that gmirror and gpart metadata overlap, and that's 
>> why I see this message?


>> Anyway, I can still boot from the primary GPT header, and here's the 
>> second message I get during boot:
>> GEOM: ad0: secondary GPT header is not in the last LBA.
>> Why does GEOM reports ad0, and not mirror/gm0 as the provider? I've 
>> used the gmirror'ed device for gpart, not ad0.

>This is how GEOM tasting works. Do you have any problem except for
those messages? What does not work?

>Also when you are writing problem report about gpart it will be not bad
to add output of `gpart show` or `gpart list` commands. >And `gmirror
list` for GEOM_MIRROR.

I opened a discussion on this before the release.
On my 8.1 system, i get this message about the corrupt headers, but it
booted on the 8.2 system it panics...

I think a lot of people are going to get bit by this.

As far as i know there is no warning anywhere that you can not use gpart
and gmirror the whole disk.

I also get this answer:
<< Maybe the boot process was made to be more standard-compliant :) >>>
That is not the way it should work, well we make the boot process more
standard compliant, bad luck for those who thougt it worked.

I also convert back to normal partitioning and gmirror.



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