Mailinglist Archive: opensuse (1473 mails)

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Re: [opensuse] UUID=>0x and LVM
  • From: "Boyd Stephen Smith Jr." <bss@xxxxxxxxxxxxxxxxx>
  • Date: Sun, 14 Jun 2009 12:36:28 -0500
  • Message-id: <200906141236.32426.bss@xxxxxxxxxxxxxxxxx>
In <8702E78B-86D7-4C69-8435-25875C189053@xxxxxxxxxxxxx>, Philip Mötteli
wrote:
Am 14.06.2009 um 03:54 schrieb Boyd Stephen Smith Jr.:
In <8FC020C1-D875-4DE3-9C4B-2698A393FADC@xxxxxxxxxxxxx>, Philip
Mötteli

wrote:
this hard-drive has changed its UUID
to 0x.
What is telling you this?
fdisk -l

That's not the UUID that LVM reads. Actually, that's not a UUID at all, it
is not enough bits. The UUID that LVM reads is stored inside the PV
metadata section written by LVM itself.

To see the UUIDs on the system as LVM sees them issue the command:
pvscan -u
as root.

Assuming nothing is wrong with the drive, you should be able to run
pvcreate
and specify the UUID that LVM is expecting and it will write the new
PV
meta-data

So allthough the drive has now the UUID of 0x, I just rewrite the old
configuration? I mean, LVM already has the old UUID for this drive
(hdc). I basically would re-write the same configuration, I already
have.

LVM writes a UUID to the PV meta-data section of each PV. This UUID is used
to identify the drive to LVM. LVM *also* writes the UUID of each PV in a VG
to the VG meta-data area. These UUIDs are used to determine which drives
belong in the VG.

If LVM is giving you messages like "could not locate physical volume with
UUID blah-blah-blah" that means it has found at least one copy of the VG
meta-data and that meta-data lists "blah-blah-blah" as the UUID of the of
the component PVs but LVM couldn't find a drive that has that UUID in its PV
meta-data section.

The pvcreate command will write a new PV meta-data section, which appears to
be corrupt--at the very least (you say) it has the wrong UUID. It would not
change the any of the VG meta-data.

If the configuration was correct, you wouldn't be getting errors. Anything
that corrects the situation is not "rewrit[ing] the same configuration".

without affecting any other sectors on the drive/partition.

That was something, I was afraid of. They haven't a backup so far.

Even if you can't mount the drive, you can take a dd_rescue copy of it
before you make changes to any of the data on it.
--
Boyd Stephen Smith Jr. ,= ,-_-. =.
bss@xxxxxxxxxxxxxxxxx ((_/)o o(\_))
ICQ: 514984 YM/AIM: DaTwinkDaddy `-'(. .)`-'
http://iguanasuicide.net/ \_/

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