[rhn-users] need advice on managing partition size (LVM / RAID hardware)

[Jesse Becker]

On Mon, Sep 27, 2004 at 10:15:03AM -0400, Frederic Medery wrote:
> I have a 1 TB RAID 5 hardware. I would like to use LVM to manage 
> partition size but  :
> When I'll add extra storage (inside the raid 5), Linux will see extra 
> free space but i won't be able to resize ma LVM partition ( i think). So 
> now, I'm thinking of NOT using LVM and create all my partition with the 
> RAID. So, when  I add extra storage, I just have to add this disk to the 
> partition that need it and then resize the File system size.

I was all set to write an email about how you can't add drives to an existing
RAID array, then found that it might be possible.  However, generally,
if you wish to add more space, you either must do one of two things:

	1) leave the existing 1TB array alone and create a new storage
	"thing" (ranging from a lone disk with no RAID, to a new RAID
	array of some level),

	2) destroy the existing RAID5 array, add the new drives, then create a new
	(and larger) array using the additional disks.

It seems that there is a tool called 'raidrecof' that might do the trick.
Make backups of your data, and have a look at it.

> Is it a good solution ? I would prefer LVM because resizing would be 
> only but cannot see how to able it with Hardware RAID 5.

I would suggest using LVM anyway, and not resize the arrays.  You already
have one RAID array.  Use this as a physical volume (/dev/sda1, or
whatever is appropriate) in a volume group (/dev/vg0, for example),
and create your logical volumes within that.  When it comes time to
add more space, create a second RAID array (/dev/sdb), and add it to
the existing volume group that you already have.  That group can then
make use of the new space, either to create additional logical volumes,
or increase the size of existing ones.

If this is hardware RAID (as opposed to software /dev/md devices), the
controller should support multiple arrays.

-- 
Jesse Becker
GPG-fingerprint: BD00 7AA4 4483 AFCC 82D0  2720 0083 0931 9A2B 06A2
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 189 bytes
Desc: not available
URL: <http://listman.redhat.com/archives/rhn-users/attachments/20040927/6ad0c505/attachment.sig>