Data Recovery Forums - Help & Discussions

gear2000 · Joined: 03 Feb 2011 Posts: 1

hi,

i'm in need of some help to recover data. please feel fre to give me any advice.

HOST OS: Centos 5.5 with Xen 3.4.3 with software RAID 1 and LVM on top of it.
GUEST OS: NexentaStor CE and Centos 5 Paravirtualization machines.

essentially, this is what happened:

1) Prior

ON HOST

/dev/md1 - software raid 1

lvm on top of /dev/md1 - contained several logical volumes.

2) What happened

ON GUEST

created a XEN VM of NexentaStor Community Edition on the HOST. Accidentally assigned /dev/md1 instead of /dev/md2.

nexenta create a zpool on top of /dev/md2. it didn't check on whether there was an existing linux lvm or anything.

i create 3 zfs filesystems on top of it.

ON HOST

i started copying files to the Nexentastor VM, and then my LVM's disppeared. it was writing on top of an existing LVM that wa
s being used. Once the ZFS encapsulated the /dev/md1 with GPT, linux couldn't read the LVM anymore.

3) NOW

i have /dev/md1 which still has the LVM information, but it's encapsulated into some GPT container. Nexenta did something to
it.

dd if=/dev/md1 bs=512 count=255 skip=1 of=/tmp/md1.txt

i looked at /tmp/md1.txt and it shows the lvm informmation along with some "binary" type headers intermixed throughout the file.

TRIEDsince it is a raid 1, i detached one member to serve as backup. i can "dd" it back to the original condition with the backup
copy of the mirror.

it looks like the original linux lvm which was directly on the top of the /dev/md1 (not a partition) is somewhat encapsulated
by what ZFS did with GPT.

i figure i need to remove the GPT and see if i can't get the LVM to be detected. right now, when i run pvscan, no volumes sho
w up. when i do an fdisk -l, it complains about not being able to read GPT.

4) HOPE

I just hope to recover what data I can. I wasn't sure if I should use testdisk or some other utility, or send it to some place to recover the data.

Gosh, I wished I didn't fat finger /dev/md1 instead of /dev/md2. Please any suggestion or direction would be very very appreciative.

Thanks,

Gary