[LUAU] Re: Linux HD Recovery

John S. Johnson jsj at amagata.com
Thu Jan 18 19:49:20 PST 2007


My adventures in hard disk recovery continues. I tried to hook up the
old primary drive as the main drive on another system but got a kernel
panic error and a reset. I decided it would be best to try to mount the
drive via an external USB hard disk enclosure and try copying the data
off. Before hooking it up, I checked the physical volumes with pvscan
and got the following:

---------------------

[root at www jsj]# /usr/sbin/pvscan

  PV /dev/hde2   VG VolGroup00   lvm2 [38.06 GB / 32.00 MB free]

  Total: 1 [38.06 GB] / in use: 1 [38.06 GB] / in no VG: 0 [0   ]

[root at www jsj]#

-----------------------

I hooked up the drive and turned it on and got the following:

-----------------------

 [root at www jsj]# /usr/sbin/pvscan

  Couldn't find device with uuid
'0caVRx-fuNp-lc2N-or5C-6Ky7-52oS-pQF0RU'.

  PV unknown device   VG VolGroup00   lvm2 [6.00 GB / 0    free]

  PV /dev/sda2        VG VolGroup00   lvm2 [1.84 GB / 64.00 MB free]

  Total: 2 [7.84 GB] / in use: 2 [7.84 GB] / in no VG: 0 [0   ]

-----------------------

 

I am worried about the "Couldn't find device with uid..." comment. My
system went down hard and I am sure the drives need to be cleaned for
inconsistencies(although I have no idea how to). Anyway, from this I can
tell that the USB drive is on /dev/sda, so I decided to use fdisk to
check out its partition table:

-----------------------

 [root at www jsj]# /sbin/fdisk /dev/sda

 

Command (m for help): p

 

Disk /dev/sda: 2113 MB, 2113413120 bytes

255 heads, 63 sectors/track, 256 cylinders

Units = cylinders of 16065 * 512 = 8225280 bytes

 

   Device Boot      Start         End      Blocks   Id  System

/dev/sda1   *           1          13      104391   83  Linux

/dev/sda2              14         256     1951897+  8e  Linux LVM

 

Command (m for help):

-----------------------

 

This looks right. Now how to mount it...it's a Linux LVM drive. I can
directly mount /dev/sda1 but not /dev/sda2 since it is Linux LVM. I
believe you are supposed to mount the volume group itself(hmm...would
there be any trouble in that /dev/hde2 and /dev/sda2 are both
automatically named VolGroup00?). As Vince suggested, I tried using
vgchange:

-----------------------

 

[root at www jsj]# /usr/sbin/lvm vgchange -a y

  2 logical volume(s) in volume group "VolGroup00" now active

-----------------------

 

So now we have two volumes active. It's time to see which volumes they
are...

-----------------------

[root at www jsj]# /usr/sbin/lvm lvscan

  ACTIVE            '/dev/VolGroup00/LogVol00' [37.53 GB] inherit

  ACTIVE            '/dev/VolGroup00/LogVol01' [512.00 MB] inherit

-----------------------

Hmm...neither seem to be my 2GB partition....not sure why...could it be
that the volumes on my other drive were named /dev/VolGroup00/LogVol00
and /dev/VolGroup00/LogVol00 as well? I'm not sure...I decided to take a
look at the volume groups via the vgdisplay command...

-----------------------

 [root at www jsj]# /usr/sbin/lvm vgdisplay -P -v

  Partial mode. Incomplete volume groups will be activated read-only.

    Finding all volume groups

    Finding volume group "VolGroup00"

  --- Volume group ---

  VG Name               VolGroup00

  System ID

  Format                lvm2

  Metadata Areas        1

  Metadata Sequence No  3

  VG Access             read/write

  VG Status             resizable

  MAX LV                0

  Cur LV                2

  Open LV               2

  Max PV                0

  Cur PV                1

  Act PV                1

  VG Size               38.06 GB

  PE Size               32.00 MB

  Total PE              1218

  Alloc PE / Size       1217 / 38.03 GB

  Free  PE / Size       1 / 32.00 MB

  VG UUID               rmtJio-1AqZ-W8ZI-rt4P-4nuD-4pAP-Jo3rGb

 

  --- Logical volume ---

  LV Name                /dev/VolGroup00/LogVol00

  VG Name                VolGroup00

  LV UUID                1fQ23c-q2Gm-VSHA-cGby-vjTp-E7BD-OsDJfZ

  LV Write Access        read/write

  LV Status              available

  # open                 1

  LV Size                37.53 GB

  Current LE             1201

  Segments               1

  Allocation             inherit

  Read ahead sectors     0

  Block device           253:0

 

  --- Logical volume ---

  LV Name                /dev/VolGroup00/LogVol01

  VG Name                VolGroup00

  LV UUID                Vm0X6G-jhjZ-SqbI-iEKg-My91-zt2y-KmlNPp

  LV Write Access        read/write

  LV Status              available

  # open                 1

  LV Size                512.00 MB

  Current LE             16

  Segments               1

  Allocation             inherit

  Read ahead sectors     0

  Block device           253:1

 

  --- Physical volumes ---

  PV Name               /dev/hde2

  PV UUID               Dvb1gT-8ZxD-JNfG-tXh9-cloY-6hNz-25BqFS

  PV Status             allocatable

  Total PE / Free PE    1218 / 1

 

-----------------------

Again, I don't see /dev/sda represented in here. Anyone know why or what
to do?

 

In case a look in my /etc/fstab may be helpful:

-----------------------

 [root at www jsj]# more /etc/fstab

# This file is edited by fstab-sync - see 'man fstab-sync' for details

/dev/VolGroup00/LogVol00 /                       ext3    defaults
1 1

LABEL=/boot             /boot                   ext3    defaults
1 2

none                    /dev/pts                devpts  gid=5,mode=620
0 0

none                    /dev/shm                tmpfs   defaults
0 0

none                    /proc                   proc    defaults
0 0

none                    /sys                    sysfs   defaults
0 0

/dev/VolGroup00/LogVol01 swap                    swap    defaults
0 0

/dev/hda                /media/cdrecorder       auto
pamconsole,exec,noauto,m

anaged 0 0

/dev/sda1               /media/usbdisk          ext3
pamconsole,exec,noauto,n

oatime,sync,managed 0 0

[root at www jsj]#

-----------------------

I'd appreciate it if anyone can give me advice for mounting the LVM
partition and maybe cleaning up the inconsistencies problem(I tried to
Ghost the HD so I could experiment with a copy of it, but Ghost bombed
out, citing inconsistencies on the disk).

Thank you very much in advance and sorry for the long post...

 

--John Johnson




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