Re: Tuning RMAN backup and recovery

On Dec 28, 2007 9:30 AM, Don Seiler <don_at_seiler.us> wrote:
>
> I'm trying to get detailed specifics on the lay of the storage
> landscape beneath ASM. As I've indicated in another thread, we're
> currently just using two 933gb LUNs for this disk group. These LUNs
> are carved from the SAN and composed of a number of disks under RAID
> 10. I'm waiting for the admin to give me info like individual disk
> size and stripe size. IIRC, each RAID group is composed of 3 data and
> 3 parity disks, the LUNs are then striped across those, and then ASM
> is striped across the (two) LUNs in the normal ASM disk group fashion.
>
> We are using external redundancy in the ASM disk group.
>
> I'll write back when I get more storage specifics.

OK I was able to get these specifics about our RMAN and ASM LUNs:

• ASM disks: both are 14 disks, RAID 10, 7D+7P
• RMAN: 12 disks, RAID 10, 6D+6P
• Disks are each 73G
• Stripe size is 64k

The D+P means data and parity for mirroring.

Re: ASM. It seems to me like we're shooting ourselves in the foot if we give ASM two big striped-and-mirrored LUNs rather than at least letting ASM handle the striping across 7 disks rather than 2. I'd like to know what people's thoughts who've had more experience with such things.

Although I digress from the immediate problem of the RMAN post-restore catalog task taking forever.

Don.

-- 
Don Seiler
http://seilerwerks.wordpress.com
ultimate: http://www.mufc.us
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