RAID controller features

Stroller stroller at stellar.eclipse.co.uk
Thu Mar 4 02:04:20 CST 2010


On 3 Mar 2010, at 19:47, Dominic Lepiane wrote:
> ...
> For example, I have a PE2900 with a PERC 5/i.  It's got a RAID1 for OS
> plus a RAID5 for data.  I tried growing the data RAID by upgrading the
> disk sizes only to find that after much fiddling and searching Online
> that some people report the upgrade "just works" and others say "it  
> just
> doesn't".

I'm not quite sure what you're doing here.

On a non-Dell 3ware 9500 SATA RAID controller I have 2 x 160gig drives  
in a RAID1. If I remove drive 1 from the array & replace it with a  
320gig, rebuild the array onto the new drive and then do the same  
thing with the second drive, it *seems* then to recognise the whole  
array as 320gig. Is this what you're trying to do? I would imagine  
this does indeed depend on the controller.

> Now on another server, ... when I called Dell support thinking maybe  
> this
> was a bug with the BIOS or some odd hardware fault, support said that
> multiple VDs on a single array wasn't "supported" though once we  
> loaded
> an OS (Windows Server 2008) on there with OM, that was exactly the
> configuration we were able to do (two VDs on one array).

I've experienced something like this myself. Worked fine to build two  
virtual disks on a single array on a PowerEdge 2800 (PERC 4e/Di) and  
install Windows 2003 on it. That ran great for 4 years, but there is  
no way in the OpenManage Server Administrator to migrate one of the  
virtual disks onto a different array.

I, too, was told the same thing you were - this configuration was not  
supported - so ended up creating a new array & migrating by cloning  
the virtual disk onto that using `dd`. That worked great - the old  
virtual disk could now be deleted. I can't now recall whether it was  
then possible to expand the remaining virtual disk to fill the first  
array or whether another round of `dd` was required (deleting the  
virtual disk & creating a new one filling the array).

I created the two virtual disks in order to separate o/s C: drive and  
data D: drive, and intuitively one might expect to be able to migrate  
a virtual drive from one set of physical disks to another. However  
this would be a full copy operation, and I don't entirely blame Dell  
for not supporting it. At the end of the day, I was just being miserly  
with disks when I originally set this up - I think it would be fair &  
reasonable to expect only one virtual disk per array; my biggest  
complaint is that the software allows you to configure multiple  
virtual disks per array like this, which may lead to problems.

Not sure how much these observations actually help you, as they seem  
not quite directly related to your issues. However I am feeling bright  
& chatty enough this morning to chime in. :D

Stroller.



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