From: Zdenek Kabelac <zkabelac@redhat.com>
To: LVM general discussion and development <linux-lvm@redhat.com>,
Brian McCullough <bdmc@bdmcc-us.com>
Subject: Re: [linux-lvm] Help restoring a corrupted PV partition ( 18th )
Date: Mon, 18 Oct 2021 23:40:39 +0200 [thread overview]
Message-ID: <b39f6785-9740-8116-3b5e-91211869ab7e@redhat.com> (raw)
In-Reply-To: <20211018180853.GF28058@bdmcc-us.com>
Dne 18. 10. 21 v 20:08 Brian McCullough napsal(a):
>
> I have had a disk go bad on me, causing me to lose one PV.
>
> If I am not providing sufficient, or the proper, information, feel free
> to ask for more.
>
>
> I seem to have retrieved the partition using ddrescue and put it on to
> a new drive, but it seems to be missing some label information, because
> pvscan doesn't recognize it as a PV partition.
>
> Using hexdump, I see the string " LVM2 " at 0x1004, but nothing before
> that. The whole 16 bytes is:
>
> 0x01000 16 d6 8e db 20 4c 56 4d 32 20 78 5b 35 41 25 72
> L V M 2
>
>
>
> I find what appears to be an LVM2 vgconfig block starting at 0x01200,
> extracted that to a file and was able to read the UUID that this PV
> should have. It is one of about a dozen that make up this VG.
>
>
> On another machine, I dumped a PV partition, and find "LABLEONE" at
> 0x200, with the same " LVM2 " at 0x01000.
>
> I was concerned that my dump was offset, but the comparison to the
> "good" one suggests that that isn't the problem, but just the missing
> "LABLEONE" and related information at 0x0200.
>
>
> How to fix?
>
> If I do a "pvcreate --uuid xxxx" would this fix that recovered partition
> so that pvscan and friends can work properly, and I can finally boot
> that machine?
Hi
It's quite important to be aware how the disk corruption happened.
Was this plain disk hw error - or some crash of raid setup ?
Normally you could restore PV with this:
pvcreate --uuid XXXX --restorefile file_with_vg_backup /dev/ddddd
vgcfgrestore --restorefile file_with_vg_backup vgname
But if the content of device was scramble by some 'raid' bug - you might have
problem to retrieve any usable data afterward.
Regards
Zdenek
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next prev parent reply other threads:[~2021-10-18 21:41 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-18 18:08 [linux-lvm] Help restoring a corrupted PV partition ( 18th ) Brian McCullough
2021-10-18 21:40 ` Zdenek Kabelac [this message]
2021-10-18 22:20 ` Brian McCullough
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