[linux-lvm] adding a bootsector to a PV destroys it ?!?

[linux-lvm] adding a bootsector to a PV destroys it ?!?

[Goetz Bock]

Hi list,

while I have tried to search the archive, I was obviousely to dump to
find what I was looking for.

I just did (on 2.4.19 with LVM 1.0.5)

pvcreate /dev/hda4
vgcreate vg00 /dev/hda4
lvcreated ...
copy ... install ...
.
.
.
vgcfgbackup
dd if=/dev/hda of=/dev/hda4 bs=512 count=1 (*)

[ reboot ]

argl /dev/hda4 is no longer a valid PV.

doing

pvcreate /dev/hda4
vgcfgrestore -f /etc/lvmconf/vg00.conf /dev/hda4

recovered all my LVs, so I'm back in the game.

Still, just to make sure:
overwriting the first 512byte of a PV destroy it?

Thanks, and keep up the good work :-)


(*) to backup LILOs boot sector, I wanted to install (shiver) W2k
    and moving lilo from MBR would allow me to recover easily. 
-- 
Goetz Bock       (c) 2002 as     blacknet.de - Munich - Germany   /"\
IT Consultant    GNU FDL 1.1    secure mobile Linux everNETting   \ /
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Re: [linux-lvm] adding a bootsector to a PV destroys it ?!?

[José Luis Domingo López]

On Sunday, 01 September 2002, at 02:26:35 +0200,
Goetz Bock wrote:

> Still, just to make sure:
> overwriting the first 512byte of a PV destroy it?
> 
If I recall correctly, metadata is placed at the beginning of each PV,
so overwriting the first 512-byte sector of it will probably render
metadata unusable for LVM.

-- 
Jose Luis Domingo Lopez
Linux Registered User #189436     Debian Linux Woody (Linux 2.4.19-pre6aa1)

Re: [linux-lvm] adding a bootsector to a PV destroys it ?!?

[Goetz Bock]

On Sun, Sep 01 '02 at 11:00, Jos� Luis Domingo L�pez wrote:
> > Still, just to make sure:
> > overwriting the first 512byte of a PV destroy it?
> > 
> If I recall correctly, metadata is placed at the beginning of each PV,
> so overwriting the first 512-byte sector of it will probably render
> metadata unusable for LVM.
thought so, but still such a PV has a couple of GiBs, it might have been
a good idea to keep the first 512bytes free for a bootloader

-- 
Goetz Bock       (c) 2002 as     blacknet.de - Munich - Germany   /"\
IT Consultant    GNU FDL 1.1    secure mobile Linux everNETting   \ /
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