[linux-lvm] Problem with partially activate logical volume
roger at beardandsandals.co.uk
Wed Jul 27 11:26:04 UTC 2022
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 <rogerheflin at gmail.com> 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 <roger at beardandsandals.co.uk>
>> Try https://www.linuxsysadmins.com/recover-a-deleted-physical-volume/?amp
>> On 26 July 2022 09:16:32 Ken Bass <daytooner at gmail.com> 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.
>>> linux-lvm mailing list
>>> linux-lvm at redhat.com
>>> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
>> linux-lvm mailing list
>> linux-lvm at redhat.com
>> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
> linux-lvm mailing list
> linux-lvm at redhat.com
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
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