From: Stuart D Gathman <stuart@gathman.org>
To: Marcin Owsiany <marcin@owsiany.pl>
Cc: linux-lvm@redhat.com
Subject: Re: [linux-lvm] Where are the data blocks of an LV?
Date: Tue, 26 Jul 2022 14:22:49 -0400 (EDT) [thread overview]
Message-ID: <2a509a35-24ab-341e-c6f-51caef2f4e1b@gathman.org> (raw)
In-Reply-To: <CAFsGsxLOyawZH7xxgfLNkh=VftBNAaDStE0XQgQTGf9NmyZ+ZQ@mail.gmail.com>
Checkout https://github.com/sdgathman/lbatofile
It was written to identify the file affected by a bad block (so it goes
the opposite direction), but the getpvmap() function obtains pe_start and
pe_size plus the list of segments. findlv() goes through the segments to
find the one an absolute sector is in. That should tell you what you want
to know.
On Fri, 22 Jul 2022, Marcin Owsiany wrote:
> I know that it is possible to find where a given logical volume's extents
> start on a PVs thanks to the information printed by lvdisplay --maps.
>
> I was also able to experimentally establish that the actual data of an LV
> starts one megabyte after that location. Is that offset documented anywhere,
> or can I somehow discover it at runtime for a given LV?
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prev parent reply other threads:[~2022-07-26 18:52 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-22 17:30 [linux-lvm] Where are the data blocks of an LV? Marcin Owsiany
2022-07-26 8:58 ` Roger James
2022-07-26 18:22 ` Stuart D Gathman [this message]
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