I got a lvm error.
I build a lvm vg on single disk, today after my reboot my computer I found the vg is lost.
I got no info when vgs, but can see those info when pvs:
PV VG Fmt Attr PSize PFree
/dev/sdb2 lvm2 --- 223.08g 223.08g
How can I restore my data now?
The recovery I began my attempt at recovery by using TestDisk run from a Knoppix CD. Unfortunately, I had already overwritten the partition table, and an exhaustive search of the hard drive for lost partitions yielded too many results. I decided to use PhotoRec instead to recover my lost files.
PhotoRec recovers files by finding deleted files and copying them to disk. This means that files should not be recovered to the same disk partition on which the deleted files reside (unless you're recovering from a disk image file), because that could lead to the deleted data being permanently overwritten.
Another important thing to remember is that PhotoRec will most likely recover a lot of files. This means that the partition on which the recovered files are to be stored should have at least as much free space as the size of the partition on which PhotoRec is searching for recovered files.
Possible setups for recovery include:
Recover the files to a separate hard drive.
Recover the files to a networked storage drive.
Recover the files to a separate partition on the same hard drive.
Image the hard drive using a tool like ddrescue and recover files using only one partition.
As I had completed erased my partitions, I could not use the third option. The second option introduces problems associated with network speed and latency. The fourth option is worth considering in the case of an incident response where the image of the hard drive is used as evidence.
I chose the first option, and installed two hard drives in a single computer. I divided the hard drive used to recover files into two major partitions; the first partition held the operating system (CentOS 4), while the second partition was set up to hold the recovered files. Partitioning in this manner is an extra precaution to prevent PhotoRec from halting the system by writing more files than the storage space allows. Another option is to run the operating system off a live CD such as Knoppix, which contains the TestDisk and PhotoRec utilities.
You can download both PhotoRec and TestDisk in a single archive file. The files photorec_static and testdisk_static are the executable files, and can be executed from the command line.
Make sure that the recovery partition is mounted (I mounted it at /var/recovery). Don't mount the hard drive that contains the deleted files; if the partition remains unmounted, you can't overwrite the data it contains.
