[CentOS-virt] RAID: by host or within KVM?

Fri Aug 10 16:28:31 UTC 2012
SilverTip257 <silvertip257 at gmail.com>

I agree with Stephen.  Option #1 is the way to go.

On all of the KVM nodes I've personally built, I use a hardware RAID
controller and let it manage the array.  You could use software RAID
on the host OS, but there are advantages of using hardware RAID
(background array initialization, battery backed).

Keep the RAID management at the hardware _or_ host OS (software raid)
level and it will simplify administration.

//  SilverTip257  //

On Fri, Aug 10, 2012 at 11:00 AM, Stephen Harris <lists at spuddy.org> wrote:
> On Fri, Aug 10, 2012 at 10:39:18AM -0400, Kanwar Ranbir Sandhu wrote:
>> 1. Let the KVM host manage the drives (i.e. RAID with LVM on top) and just
>> assign the single volume to OMV. OMV will see it as one HD.
>> 2. Assign the individual drives to the OMV KVM, and let OMV manage the
>> creation, management, etc.
> I recommend option 1 simply because of recovery methodology.  If you
> lose a disk and replace it, if the host controls the RAID then you have
> one point of repair and the VMs don't even notice.  If, however, each
> VM does RAID itself then _each_ VM will need to perform disk replace
> and rebuild, which is a lot of admin overhead.  Also that could cause
> a lot of disk contention and slow down the rebuild.
> Today you only have one VM.  Tomorrow? :-)
> --
> rgds
> Stephen
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