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Hi,

I have 2 USB HDDs with one partition each combined in an LVM. Due to service
operations the PC was shut down. After reboot the lvm didn't start again.
The disks and their partitions are available, but the lvm device isn't
created, mounting fails and boot process stops. In /etc/lvm/backup I found
data about the former lvm system.

How can I reconstruct the lvm without data loss?


Thomas

Thomas Olschewski wrote:
> Hi,
>
> I have 2 USB HDDs with one partition each combined in an LVM. Due to service
> operations the PC was shut down. After reboot the lvm didn't start again.
> The disks and their partitions are available, but the lvm device isn't
> created, mounting fails and boot process stops. In /etc/lvm/backup I found
> data about the former lvm system.
>
> How can I reconstruct the lvm without data loss?

A distribution like SUSE has a really good rescue mode. You can
basically scan for your lvm devices and (most likely) then rebuild
your initrd (I'm thinking your root is under LVM??). Regardless,
the best thing to do probably is to boot a rescue image that
has the LVM tools and start there.

I know that's not much to go on... you'll have to provide a lot more
information before I could issue a command-by-command recommendation.

In comp.os.linux.setup Thomas Olschewski <junk@innomic.de>:
> Hi,

> I have 2 USB HDDs with one partition each combined in an LVM. Due to service
> operations the PC was shut down. After reboot the lvm didn't start again.
> The disks and their partitions are available, but the lvm device isn't
> created, mounting fails and boot process stops. In /etc/lvm/backup I found
> data about the former lvm system.

Whoever had the idea of this setup, it is just like asking for
trouble.

> How can I reconstruct the lvm without data loss?

See www.tldp.org (LVM howto) for hints to recover. Make an image
first before starting to recover.

Good luck

--
Michael Heiming (X-PGP-Sig > GPG-Key ID: EDD27B94)
mail: echo zvpunry@urvzvat.qr | perl -pe 'y/a-z/n-za-m/'
#bofh excuse 415: Maintenance window broken

"Michael Heiming" <michael+USENET@www.heiming.de> schrieb im Newsbeitrag
news:tash14-a81.ln1@news.heiming.de...
> Whoever had the idea of this setup, it is just like asking for
> trouble.

Well, there aren't too important data on this lvm (video records of my
MythTV box). But recovering the movie recorded yesterday would be fine.


Thomas

"Chris Cox" <ccox_nopenotthis@airmail.net> schrieb im Newsbeitrag
news:12kcd5il5sauo28@corp.supernews.com...
> A distribution like SUSE has a really good rescue mode. You can
> basically scan for your lvm devices and (most likely) then rebuild
> your initrd (I'm thinking your root is under LVM??). Regardless,

No, root isn't under LVM. LVM contains a number of TV records "only".
I have the system up, commented the fstab entry out. All LVM tools are
available. But I don't know how to recover the LVM. I created it by Suse's
yast tool. When I start LVM section in yast, it comes up with a window for
LVM creation. It doesn't know about the former created LVM. Creating a new
LVM seems dangerous for me. So I stopped here and finished yast.

> the best thing to do probably is to boot a rescue image that
> has the LVM tools and start there.
>
> I know that's not much to go on... you'll have to provide a lot more
> information before I could issue a command-by-command recommendation.

Here it comes.
pvscan
PV /dev/sde1 VG mediaLVM lvm2 [465,76 GB / 0 free]
PV /dev/sdf1 VG mediaLVM lvm2 [465,76 GB / 16,00 MB free]
Total: 2 [931,52 GB] / in use: 2 [931,52 GB] / in no VG: 0 [0 ]

vgscan
Reading all physical volumes. This may take a while...
Found volume group "mediaLVM" using metadata type lvm2

fstab entry:
/dev/mediaLVM/vol1 /home/media_2 reiserfs acl,user_xattr 1
2

However, I have no /dev/mediaLVM.

ls /etc/lvm/backup/
.. .. mediaLVM system

ls /etc/lvm/archive/
.. .. mediaLVM_00000.vg mediaLVM_00001.vg system_00000.vg
system_00001.vg


Thomas

Thomas Olschewski wrote:
> "Chris Cox" <ccox_nopenotthis@airmail.net> schrieb im Newsbeitrag
> news:12kcd5il5sauo28@corp.supernews.com...
>>A distribution like SUSE has a really good rescue mode. You can
>>basically scan for your lvm devices and (most likely) then rebuild
>>your initrd (I'm thinking your root is under LVM??). Regardless,
>
> No, root isn't under LVM. LVM contains a number of TV records "only".
> I have the system up, commented the fstab entry out. All LVM tools are
> available. But I don't know how to recover the LVM. I created it by Suse's
> yast tool. When I start LVM section in yast, it comes up with a window for
> LVM creation. It doesn't know about the former created LVM. Creating a new
> LVM seems dangerous for me. So I stopped here and finished yast.
>
>>the best thing to do probably is to boot a rescue image that
>>has the LVM tools and start there.
>>
>>I know that's not much to go on... you'll have to provide a lot more
>>information before I could issue a command-by-command recommendation.
>
> Here it comes.
> pvscan
> PV /dev/sde1 VG mediaLVM lvm2 [465,76 GB / 0 free]
> PV /dev/sdf1 VG mediaLVM lvm2 [465,76 GB / 16,00 MB free]
> Total: 2 [931,52 GB] / in use: 2 [931,52 GB] / in no VG: 0 [0 ]
>
> vgscan
> Reading all physical volumes. This may take a while...
> Found volume group "mediaLVM" using metadata type lvm2
>
> fstab entry:
> /dev/mediaLVM/vol1 /home/media_2 reiserfs acl,user_xattr 1
> 2
>
> However, I have no /dev/mediaLVM.

Try running vgmknodes as root.

>
> ls /etc/lvm/backup/
> . .. mediaLVM system
>
> ls /etc/lvm/archive/
> . .. mediaLVM_00000.vg mediaLVM_00001.vg system_00000.vg
> system_00001.vg
>
>
> Thomas
>
>

> Try running vgmknodes as root.

vgmknodes -v
Finding all logical volumes

But a /dev/mediaLVM still doesn't exist.


Thomas

A lvchange -ay /dev/mediaLVM/vol1 did it.

I think problem could be that I work without initrd. When fstab entries are
mounted, USB devices are not ready. LVM is not active without USB HDDs and
fstab can't mount the LVM.


Thomas

Thomas Olschewski wrote:
> A lvchange -ay /dev/mediaLVM/vol1 did it.

That was going to be my next suggestion...
(beat me to it)

>
> I think problem could be that I work without initrd. When fstab entries are
> mounted, USB devices are not ready. LVM is not active without USB HDDs and
> fstab can't mount the LVM.

Sounds very likely. Any reason for not using initrd?