Expanding disk space in a RAID10 on R710

cupertino cupertino at gmx.net
Fri Apr 13 11:38:56 CDT 2012


I think there was a discussion about this before on this list. 

Option 1 doesn't work at all. After replacing and rebuilding all drives
you end up with a virtual disk of exactly the same space as before, but
with more free space in the RAID group. Unfortunately you can't create
another virtual disk in that free space, because RAIDx0 RAID groups can
only contain one virtual disk (afaik). Besides it assume you want
continuous space after the expansion. 

As for option 2, I would have said, why not. But I checked and it seems
you're right:
http://support.dell.com/support/edocs/software/svradmin/6.5/en/OMSS/HTML/vdmgmt.htm#wp1233768 

But there is an 3rd option that came out of the last discussion. It sure
isn't a 'supported' way, but I tried it successfully on a Perc6/i and a
RAID5 (so I'm not 100% sure if it works for a RAID10 too). 
Do it as follows: replace all hard drives one by one until all new ones
are installed and sync'ed ... go to the CTRL+R BIOS and note all
essential properties of your virtual disk (esp. segment size + which
hard drive belongs to which span of the RAID) ... delete your virtual
disk ... create a new RAID10 with exact same settings, except the
virtual disk size -> leave here the full available capacity ... now an
very important point: DO NOT INITIALIZE your new RAID10 ... boot your
OS. 
If everything went well you will have a disk drive with the capacity of
your new RAID10 and a partition on it with the capacity of your old
RAID10. Now you can extend that partition with any tool of your choice
(I did it with gparted). 

As I said, my RAID was a RAID5 of 6 disks and I don't know if there are
any restrictions that prevent it form working with a RAID10. Maybe
someone else can give feedback about it. 
No guarantee! And better have a backup ready ;-) 


On Tue, 2012-04-10 at 18:59 -0400, Brian Mathis wrote:
> I need to expand the disk space on an R710 with a PERC6/i.  It is
> currently configured with 4 drives in a RAID10 with 1 hot spare.  This
> is with 450GB disks.  I see 2 options without going to external
> storage:
> 
> 1. Swap out each of the 4 drives, one at a time, with larger ones,
> then expand the RAID to fill the empty space.
> 
> 2. Get rid of the hot spare and use the 2 remaining slots to expand
> the RAID10 to 6 drives, and keep some cold spares on the shelf.
> 
> Has anyone performed either of these types of expansions?  The PERC6
> docs mention that Online Capacity Expansion is not available for
> RAID10, but does that apply for swapping drives for bigger ones, just
> adding new drives, or both?  Would any of these be possible, even if
> performed offline, without losing data?
> 
> 
> ❧ Brian Mathis
> 
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