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From: Roger James <>
To: LVM general discussion and development <>
Subject: Re: [linux-lvm] Problem with partially activate logical volume
Date: Wed, 27 Jul 2022 12:26:04 +0100	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

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The procedure outlined should at least get you back to a state where the lv 
is consistent but with blank sectors where the data is missing. I would 
suggest using dd to make a backup partition image. Then you can either work 
on that or the original to mend the fs.

On 27 July 2022 11:50:07 Roger Heflin <> wrote:

> I don't believe that is going to work.
> His issue is that the filesystem is refusing to work because of the
> missing data.
> man debugfs
> It will let you manually look at the metadata and structures of the
> ext2/3/4 fs.  You will likely need to use the "-c" option.
> It will be very manual and you should probably read up on the fs
> structure a bit.
> A data recovery company could get most of the data back, but they
> charge 5k-10k per TB, so likely close to 100k US$.
> And the issues will be that 1/3 of the metadata was on the missing
> disk, and some of the data was on the missing disk.
> I was able to do debugfs /dev/sda2  (my /boot) and do an ls and list
> out the files and then do a dump <filename> /tmp/junk.out and copy out
> that file.
> So the issue will be writing up a script to do lses and find all of
> the files and dump all of the files to someplace else.
> On Wed, Jul 27, 2022 at 2:39 AM Roger James <> 
> wrote:
>> Try
>> On 26 July 2022 09:16:32 Ken Bass <> wrote:
>>> (fwiw: I am new to this list, so please bear with me.)
>>> Background: I have a very large (20TB) logical volume consisting of 3 
>>> drives. One of those drives unexpectedloy died (isn't that always the case 
>>> :-)). The drive that failed happened to be the last PV. So I am assuming 
>>> that there is still 2/3 of the data still intact and, to some extent, 
>>> recoverable. Although, apparently the ext4 fs is not recognised.
>>> I activated the LV partially (via -P). But running any utility on that (eg: 
>>> dumpe2fs, e2fsck, ...) I get many of these  in dmesg:
>>> "Buffer I/O error on dev dm-0, logical block xxxxxxx, async page read."  
>>> The thing is, the xxxxxxx block is on the missing drive/pv.
>>> I have also tried some recovery software, but eventually get these same 
>>> messages, and the data recovered is not really useful.
>>> Please help! How can I get passed that dmesg error, and move on. 14TB 
>>> recovered is better than 0.
>>> TIA
>>> ken
>>> _______________________________________________
>>> linux-lvm mailing list
>>> read the LVM HOW-TO at
>> _______________________________________________
>> linux-lvm mailing list
>> read the LVM HOW-TO at
> _______________________________________________
> linux-lvm mailing list
> read the LVM HOW-TO at

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linux-lvm mailing list
read the LVM HOW-TO at

  reply	other threads:[~2022-07-28  8:12 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-25 14:48 [linux-lvm] Problem with partially activate logical volume Ken Bass
2022-07-26  8:50 ` Roger James
2022-07-27 10:49   ` Roger Heflin
2022-07-27 11:26     ` Roger James [this message]
2022-08-03 21:31       ` Ken Bass
2022-08-04 11:07         ` Roger Heflin
2022-08-05 12:03         ` Zdenek Kabelac
2022-08-05 12:42           ` Ken Bass
2022-07-27 19:56 ` Zdenek Kabelac

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