[linux-lvm] Best practice: metadata backup

[paddy at panici.net]

On Tue, Aug 07, 2007 at 08:01:53PM +0100, Alasdair G Kergon wrote:
> > AIX treats the boot LV specially, and ensures
> > that its PEs are contiguous at the beginning of the disk(s).  
> 
> Nothing is stopping a linux installer doing that today:
>   --alloc contiguous and specify the extents.

(its been a long time but) last time I looked there was no facility
to flag an LV in a manner that would accord it treatment from the
various utilities appropriate to it's status as a boot volume
(such as, for example, not moving about). Of course, when I looked
there wasn't any functionality in the utilities that did anything
to worry about :-) (but user-space code is easier written than 
on-disk representations are changed)

(unless its already been done ...) by the time anyone gets around to it,
the various bios limitation of PCs, etc will all be just a memory.

> But if grub supports LVM2 properly (add a trivial mapping layer from LV
> extents to physical sectors, then populate it from the LVM2 metadata
> across an agreed interface from a library maintained as part of the lvm2
> package) it won't require anything like that of course - the hardest
> problem I think is actually for it to identify the right disks to use.

(and yet strangely we all manage to boot ... !?!? )

... or everyone uses a boot-loader that reads filesystems, and they all
learn to read LVM too :-)

Regards,
Paddy