[linux-lvm] Volume Group with 4 HDs- one crashed

[linux-lvm] Volume Group with 4 HDs- one crashed

[nik-da-3'9'']

Hello ,

I'm having a hard time with LVM, in my PC I have setup a VG with 4
harddisks, and one of the HDs crashed. Well, I know I should have
backed up the data,
which I did, but the backup is far too old. You know how hard it is to backup
big big HDs/partitions w/o having bunches of backup media. Anyway, I have
consulted Heinz, who was so kind pointing to LVM2, with its help it should have
been possible to mount the VG partially. What I did was:

1. upgrade my kernel, so I could use the device-mapper, which is important
for LVM2
2. installed LVM2
3. tried "vgchange -P -ay", which gave me following output:

> -----
>   3 logical volume(s) in volume group "data" now active
>     Finding volume group "mpeg"
>   3 PV(s) found for VG mpeg: expected 4
>   Logical volume (mp3) contains an incomplete mapping table.
>     2 logical volume(s) in volume group "mpeg" already active
>   3 PV(s) found for VG mpeg: expected 4
>   Logical volume (mp3) contains an incomplete mapping table.
>     Found volume group "mpeg"
>   3 PV(s) found for VG mpeg: expected 4
>   Logical volume (mp3) contains an incomplete mapping table.
>     Found volume group "mpeg"
>   3 PV(s) found for VG mpeg: expected 4
>   Logical volume (mp3) contains an incomplete mapping table.
>     Found volume group "mpeg"
>   3 PV(s) found for VG mpeg: expected 4
>   Logical volume (mp3) contains an incomplete mapping table.
>     Found volume group "mpeg"
>     Activated logical volumes in volume group "mpeg"
>   2 logical volume(s) in volume group "mpeg" now active
> ----
> 
> vgdisplay :
>    Finding volume group "mpeg"
>  3 PV(s) found for VG mpeg: expected 4
> Volume group "mpeg" doesn't exist
> 
> ----

even vgscan did not help:

: # LVM2.1.95.12/tools/lvm vgscan -v
    Wiping cache of LVM-capable devices
    Wiping internal cache
  Reading all physical volumes.  This may take a while...
    Finding all volume groups
    Finding volume group "data"
  Found volume group "data" using metadata type lvm1
    Finding volume group "mpeg"
  3 PV(s) found for VG mpeg: expected 4
  Volume group "mpeg" not found

: # mount -a
mount: special device /dev/mpeg/mp3 does not exist
mount: special device /dev/mpeg/movie does not exist

VG "data" is a VG on different SCSI-HDs (which is backed up on a reg
basis... anyway this VG was never touched, as it didnt crash).

I also remove the devnodes left by LVM 1 (/dev/mpeg/mp3 /dev/mpeg/mpvie),
but still I cant access the VG's.

What to do next? Any help is really appreciated, as there is still lots of
important data on the VGs.

Thanks

-- 
Regards,
 nik-da-3'9''
 mailto:nik39.at.gmx.dot.net@check.this.mailadress.com

Re: [linux-lvm] Volume Group with 4 HDs- one crashed

[Alasdair G Kergon]

On Fri, Jan 10, 2003 at 02:38:35PM +0100, nik-da-3'9'' wrote:
> >   2 logical volume(s) in volume group "mpeg" now active
So did that not activate 2 of the logical volumes?

You have to add '-P' to *every* tool that you want to attempt
to use volume groups that are Partially missing.
(But tools only support the flag where it makes sense to.)

>   Found volume group "data" using metadata type lvm1
So it found that OK.

> I also remove the devnodes left by LVM 1 (/dev/mpeg/mp3 /dev/mpeg/mpvie),
> but still I cant access the VG's.
Recent LVM2 tarballs deal OK with any nodes left behind like that.
What version are you using?
 
> What to do next? Any help is really appreciated, as there is still lots of
> important data on the VGs.
 
Read the -P section of 'man lvm' for extra hints on recovery: depends
if you're able to replace the disk with another, or if you want to
remove the disk from the VG completely.

See also the thread a few days back:
  Re: [linux-lvm] problem

Alasdair
-- 
agk@uk.sistina.com

Re: [linux-lvm] Volume Group with 4 HDs- one crashed

[Alasdair G Kergon]

On Fri, Jan 10, 2003 at 02:12:57PM +0000, Alasdair Kergon wrote:
> > I also remove the devnodes left by LVM 1 (/dev/mpeg/mp3 /dev/mpeg/mpvie),
> > but still I cant access the VG's.
> Recent LVM2 tarballs deal OK with any nodes left behind like that.
> What version are you using?
Ah you said: .12
That change went into .13
  
vgdisplay wouldn't show them because you didn't add -P

Do a 'vgchange -an -P' and then try activating them again.

Try 'lvdisplay -P'  to check if they're active, or  check the attr. 
columns (see man page) in the new 'lvs -P' command.

Alasdair
-- 
agk@uk.sistina.com