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Date: Sat, 13 Jun 2015 00:01:25 +0800
From: Julian Elischer <julian@freebsd.org>
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To: Felipe Monteiro de Carvalho <felipemonteiro.carvalho@gmail.com>,
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Subject: Re: Uberblock location
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On 6/12/15 9:49 PM, Felipe Monteiro de Carvalho wrote:
> Hello,
>
> I am writing a program to read ZFS partitions, and although I already
> read a lot of documentation, there is 1 problem which is blocking me:
> How does the driver find the uberblock?
>
> I know, I can just get any test volume, find the ZFS uberblock and in
> my case it is positioned in 0x20C00 and there are lots and lots of
> copies (older versions?) of it.
>
> But there is no guarantee that it doesn't just happen to be in this
> position in my image and in another version it would be elsewhere, so
> I need the algorithm utilized to find it.

I presume you have looked at the zfs reading library in the bootblocks?

>
> Any ideas?
>
> thanks,