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

Marin Atanasov Nikolov dnaeon at gmail.com
Sat Feb 26 18:53:44 UTC 2011

2011/2/26 Andrey V. Elsukov <bu7cher at yandex.ru>:
> 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 and
> 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?
> No.
>> 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?

No, no other issues noticed.

> 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.

Would do that, but unfortunately as mentioned I was running a Fixit
image locally, so the only thing I got was a lit of paper and a pen to
write down the messages :)

Anyway, I've switched back to partition mirroring, which is good
enough for me. Redundancy is still present in case of a disk failure
since the second disk also contains bootcode and it boots up normally.

Thanks for the feedback.


> --
> WBR, Andrey V. Elsukov

Marin Atanasov Nikolov

dnaeon AT gmail DOT com
daemon AT unix-heaven DOT org

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