[CentOS] Recovering LVM after crash

Emmanuel Noobadmin

centos.admin at gmail.com
Wed Dec 23 21:12:50 UTC 2015


I've been trying to cover data from a disk that appeared to had been
corrupted after a power outage. The original setup was lvm on md raid
1 which appears to be what is complicating the issue. Apart from
/boot, everything was on LVM partitions so I don't have any backup lvm
information.

Following various guides online, I've recreated duplicated the raid
partition with dd onto a new disk, recreated the raid 1 array with
missing device, but the pv cannot be found.

I've tried to find the lvm uuid using this guide
https://www.howtoforge.com/recover_data_from_raid_lvm_partitions but
despite dumping twice the data to file, there are no plain text
configuration information. The drives are not encrypted so that isn't
likely to be the problem.

I also used testdisk to try to recover the partitions but it says they
cannot be recovered. During analysis, it was able to detect the lvm
partitions, extracted output:
Linux LVM  1069 146 38 60799 228 29 959567608
Linux  1069 179  7 57740  22 10  910409728
Linux  790  66 45 59780 237 33  947685112
Linux  1069 179  7 57740  22 10  910409728
Linux  29283 103  5 85953 201  8  910409728
Linux  29292 181 10 85963  24 13  910409728

The numbers are start CHS, end CHS and size in sectors. There seems to
be way more possible partitions than there should be, possibly results
of previous LV resizing.

With only such data left, is there any possible way to reconstruct the
PV/VG/LV without the uuid and recover data?



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