[linux-lvm] Adding a mirror after-the-fact

[Heinz J . Mauelshagen]

On Wed, Aug 15, 2001 at 11:30:04PM +0200, Luca Berra wrote:
> On Wed, Aug 15, 2001 at 10:56:23AM +0200, Heinz J . Mauelshagen wrote:
> > On Tue, Aug 14, 2001 at 05:11:59PM -0400, Jason Tackaberry wrote:
> > > I know this isn't strictly an LVM question, but ...
> > > 
> > > Suppose I have a volume group with 1 physical volume, say a 9GB disk.
> > > Now, after some time, I decide I want to mirror this VG with another 9GB
> > > disk.  What options do I have?  AFAICS, the only way to do this would be
> > > to start from scratch?  This is a pretty simple and presumably common
> > > thing to want to do, so I hope I'm wrong.  :)
> > 
> > Yes, you are (with 2.4 kernels) ;-)
> > 
> > You could either mirror the whole disk using MD *without* persistent superblocks
> > 
> raid superblock is at end of disk, so you could also
> create an lv with only the last PE of the PV and NEVER USE it

Luca,

that's hard to achive in most production situations.
If you allocate that last PE to and LV you potentially won't recognize it
and tamper over the MD superblock later.


> 
> L.
> 
> -- 
> Luca Berra -- bluca at comedia.it
>         Communication Media & Services S.r.l.
>  /"\
>  \ /     ASCII RIBBON CAMPAIGN
>   X        AGAINST HTML MAIL
>  / \
> _______________________________________________
> linux-lvm mailing list
> linux-lvm at sistina.com
> http://lists.sistina.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://www.sistina.com/lvm/Pages/howto.html

-- 

Regards,
Heinz    -- The LVM Guy --

*** Software bugs are stupid.
    Nevertheless it needs not so stupid people to solve them ***

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

Heinz Mauelshagen                                 Sistina Software Inc.
Senior Consultant/Developer                       Am Sonnenhang 11
                                                  56242 Marienrachdorf
                                                  Germany
Mauelshagen at Sistina.com                           +49 2626 141200
                                                       FAX 924446
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-