On Mon, Oct 18, 2021 at 11:40:39PM +0200, Zdenek Kabelac wrote: > 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. Thank you for the thoughts, Zdenek. No, it was a hardware failure. Bad blocs, unreadable sectors, etc. According to ddrescue, this partition was recovered without any problems, although, as I observe later, the first part of the partition is zero. > > > >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 > _______________________________________________ linux-lvm mailing list linux-lvm@xxxxxxxxxx https://listman.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
