[linux-lvm] vgscan can't find vg after system crash

[Jahns Volker Dr.]

vgscan will not find any volume groups after system crash, where one pv was
lost.


pvdisplay reports
	--- Physical volume ---
PV Name               /dev/hdb3
VG Name               vg01
PV Size               5.86 GB / NOT usable 264 KB [LVM: 235 KB]
PV#                   1
PV Status             NOT available
Allocatable           yes (but full)
Cur LV                1
PE Size (KByte)       4096
Total PE              1500
Free PE               0
Allocated PE          1500
PV UUID               /dev/h-db3

Other than vgscan I have tried to restore by using the vgcfgrestore tool

cp /etc/lvmconf/vg01.conf /etc/lvmtab.d/vg01
echo -ne 'vg01\0' >/etc/lvmtab

vgcfgrestore -n vg01 exits w/ error message:

vgcfgrestore -- ERROR: different structure size stored in
"/etc/lvmconf/vg01.conf" than expected in file vg_cfgrestore.c [line 120]
vgcfgrestore -- ERROR "vg_cfgrestore(): read" restoring volume group "vg01"


Otherwise, pvdata reports
--- Physical volume ---
PV Name               
VG Name               vg01
PV Size               5.86 GB / NOT usable 264 KB [LVM: 235 KB]
PV#                   1
PV Status             NOT available
Allocatable           yes (but full)
Cur LV                1
PE Size (KByte)       4096
Total PE              1500
Free PE               0
Allocated PE          1500
PV UUID               /dev/h-db3

--- Volume group ---
VG Name               
VG Access             read/write
VG Status             NOT available/resizable
VG #                  0
MAX LV                256
Cur LV                1
Open LV               0
MAX LV Size           255.99 GB
Max PV                256
Cur PV                2
Act PV                2
VG Size               7.18 GB
PE Size               4 MB
Total PE              1838
Alloc PE / Size       1838 / 7.18 GB
Free  PE / Size       0 / 0
VG UUID               vg01

--- List of logical volumes ---

pvdata -- logical volume "/dev/vg01/lvol1" at offset   0
pvdata -- logical volume struct at offset   1 is empty
pvdata -- logical volume struct at offset   2 is empty
pvdata -- logical volume struct at offset   3 is empty
pvdata -- logical volume struct at offset   4 is empty
pvdata -- logical volume struct at offset   5 is empty
pvdata -- logical volume struct at offset   6 is empty
...

--- List of physical extents ---

PE: 00000  LV: 001  LE: 00000
PE: 00001  LV: 001  LE: 00001
PE: 00002  LV: 001  LE: 00002
PE: 00003  LV: 001  LE: 00003
PE: 00004  LV: 001  LE: 00004
PE: 00005  LV: 001  LE: 00005
PE: 00006  LV: 001  LE: 00006
...
LE

pvdata exits w/ error message:
pvdata -- ERROR "pv_read_uuidlist(): open" reading physical volume uuid list
from physical volume "/dev/hdb3"

How come that pvdata doesn't show the PV resp. VG name? 
Is it possible to change the PV status to available and how would I do so?

Is there anything I can do to restore the data present on the harddrive?
That would be really great.


--
Volker Jahns, Volker.Jahns at dpma.de