Recovering from a disk failure

Hi all,

I was preparing to move data residing on a LV to a RAID5 array when the cruel hand of irony slapped me, and one of the drives in my LV died. I have not migrated any data off of the LV.

Here is my setup:
* Linear lvm: 80GB, 80GB, 40GB ( I think in this order also, but I"m not 100percent sure
* The 40GB died: doesn't power on, isn't detected by BIOS.

I've searched the archives, and there seems to be 2 solutions:
* Bottom up solution- get a replacement drive, do pvcreate, restore the vg data onto the drive, run vgscan and hope

I tried this, but I can't find the UUID for the missing drive (because I can't read off of it) so there's no way for me to assign the replacement drive the correct UUID. I've tried using vgcfgbackup/restore (from LVM2 with -P flag) but it doesn't record the UUID for the missing drive.

* Top down solution -get device-mapper and LVM2, vgscan, vgchange -ay -P, mount the filesystem and hope

I tried this, but the filesystem on the LV is reiserfs and it won't allow me to mount the LV. I would try reiserfsck and other tools, but the VG is incomplete and is only accessible read-only.

Below is the output of vgdisplay -v -P (from LVM2):

Thanks for any assistance,

Thien

-------------------------
Partial mode. Incomplete volume groups will be activated read-only.
Finding all volume groups
Finding volume group "vg_home"
2 PV(s) found for VG vg_home: expected 3
Logical volume (lv_home) contains an incomplete mapping table. --- Volume group ---

  VG Name               vg_home
  System ID             lisa1026448546
  Format                lvm1
  VG Access             read
  VG Status             resizable
  MAX LV                256
  Cur LV                1
  Open LV               0
  Max PV                256
  Cur PV                2
  Act PV                2
  VG Size               188.12 GB
  PE Size               4.00 MB
  Total PE              48160
  Alloc PE / Size       48160 / 188.12 GB
  Free  PE / Size       0 / 0
  VG UUID               BHXFw1-6juI-h8jW-fxBQ-H7EW-ng14-6iGQX2

--- Logical volume ---

  LV Name                /dev/vg_home/lv_home
  VG Name                vg_home
  LV UUID                000000-0000-0000-0000-0000-0000-000000
  LV Write Access        read/write
  LV Status              NOT available
  LV Size                188.12 GB
  Current LE             48160
  Segments               9544
  Allocation             next free
  Read ahead sectors     1024

--- Physical volumes ---

  PV Name               /dev/discs/disc1/disc
  PV UUID               OUcSLF-p0XM-5Qhc-qViC-hhZG-ALcl-pkdc00
  PV Status             allocatable
  Total PE / Free PE    19540 / 0

  PV Name               /dev/discs/disc2/disc
  PV UUID               24IIKM-aegb-RuxL-27ro-AMLZ-bU9K-XFsHGS
  PV Status             allocatable
  Total PE / Free PE    19078 / 0

Run LVM1's "pvdata -U" on one of the accesable drives to get the list of all PV UUIDs.

The LVs are writable still so you should be able to run the filesystem check. You probably want to do a block level backup before that.

Regards,
Heinz -- The LVM Guy --

*** Software bugs are stupid.
Nevertheless it needs not so stupid people to solve them ***

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Heinz Mauelshagen Sistina Software Inc.
Senior Consultant/Developer Am Sonnenhang 11
56242 Marienrachdorf Germany
[email protected] +49 2626 141200

                                                       FAX 924446

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