Re: [linux-lvm] LVM2 on hardware RAID

[paddy <paddy@panici.net>]

On Fri, Aug 11, 2006 at 12:48:42PM -0400, Musil, William wrote:
> Hello all.
> 
> I have an issue, that I am not sure how to address.
> 
> How can I resize the physical volume if I change the geometry of the disk
> (non-destructive resize of RAID volume at the hardware level) 
> I can see that the OS has picked up the new size of the disk and I would like
> to resize the existing pv. I don't know how.
> 
> I started with a hardware raid 5 (400GB), linux automatically recognizes disk
> as /dev/sdb
> 
> a simplistic representation of the setup is as follows
> 
> pvcreate /dev/sdb
> vgcreate VolGroup10 /dev/sdb
> lvcreate -n LogVol10 VolGroup10
> mkfs.ext3 /dev/mapper/VolGroup10-LogVol10
> 
> I have added a disk and expand the array to 600GB I can still see every thing
> but I don't know how to extend the PV.
> 
> filesystems OK
> logical volumes OK
> volume groups OK
> 
> linux sees /dev/sdb as 600GB
> pvs shows pv /dev/sdb is 400GB. I wish to, non-destructively, reinitialize
> /dev/sdb so that pvs shows 600GB. how?

online or offline ?

I'm not aware of any tool that will resize your PV online.  I can't immediately
think that it would be hugely difficult, but it's a piece of work :-)

as for offline, you could do that in an afternoon with shell and dd :-)

Other possible strategies include, having partitioned your raid in the first
place (yes I know this is silly, but you can see what I mean), or perhaps
converting to some other VM software that can do what you need (like, will
EVMS do this??)  Perhaps there is a way to emulate the 'having partitioned
first strategy' and make the new 200G addressable as a seperate block
device, at which point a pvmerge command would come in handy :-)
(of course that would be easier if the PEs were PE size aligned to the
underlying device, but you could take account of that in where you 
started your new PV :-)

Or perhaps some kind soul will point you to something I have missed.

Good Luck.

Regards,
Paddy
-- 
Perl 6 will give you the big knob. -- Larry Wall