[parted-devel] LVM partition "fixed" with GPT parition table.

[Paul Robinson]

Firstly, apologies if this is not an appropriate forum for what is effectively a support request but my Goolging so far today has turned up neither an answer to my question or a more appropriate forum for the question.

I'm looking for information about what is done to a partition in the situation when this message appears:

"Warning: /dev/emcpoweri contains GPT signatures, indicating that it has a GPT table.  However, it does not have a valid fake msdos partition table, as it should.  Perhaps it was
corrupted - possibly by a program that doesn't understand GPT partition tables.  Or perhaps you deleted the GPT table, and are now using an msdos partition table.  Is this a GPT partition table?" [and subsequently the answer given was "yes"]

I have a hunch that this was what happened to a partition that I'm currently having a problem with.

The LUN in question was actually an LVM PV across the whole device (no partition table). Size is about 4.8GB.
Between reboots on the 5th Jan and this morning (11th Jan) I suspect that one of the team supporting this server have possibly used parted to create a GPT partition table where there shouldn't be one. As a result LVM will not recognise the PV and all data is therefore inaccessible.

The first (non-null) bytes of the partition prior to the changes looked like:

0000200: 4c41 4245 4c4f 4e45 0100 0000 0000 0000  LABELONE........
0000210: 46f3 997f 2000 0000 4c56 4d32 2030 3031  F... ...LVM2 001
0000220: 655a 5871 7631 4b30 7772 624b 4853 6835  eZXqv1K0wrbKHSh5
0000230: 7a65 4b58 4255 7831 5932 5657 5741 474b  zeKXBUx1Y2VWWAGK

After the changes:

00001f0: 0000 0000 0000 0000 0000 0000 0000 55aa  ..............U.
0000200: 4546 4920 5041 5254 0000 0100 5c00 0000  EFI PART....\...
0000210: 3903 a378 0000 0000 0100 0000 0000 0000  9..x............
0000220: ffff 7f32 0200 0000 2200 0000 0000 0000  ...2....".......
0000230: deff 7f32 0200 0000 6ad0 e561 2eb9 1c43  ...2....j..a...C
0000240: a47d 0862 12fc eb38 0200 0000 0000 0000  .}.b...8........
0000250: 8000 0000 8000 0000 8a4b 3819 0000 0000  .........K8.....
Followed later by:
0008000: 4c41 4245 4c4f 4e45 0100 0000 0000 0000  LABELONE........
0008010: 3d79 02cd 2000 0000 4c56 4d32 2030 3031  =y.. ...LVM2 001
0008020: 6164 5952 3977 4f34 484b 3831 6850 4f58  adYR9wO4HK81hPOX
0008030: 6e72 5949 4c74 664c 564a 3231 3164 676b  nrYILtfLVJ211dgk

Has anyone got any advice as to how to go about undoing this mess?

Please ask if additional information is required.

Thanks in advance, Paul.