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Re: Tuning RMAN backup and recovery

From: Don Seiler <>
Date: Fri, 28 Dec 2007 09:30:13 -0600
Message-ID: <>

I'm getting bit HARD by this one again. This time I'm using RMAN duplication to restore from production onto development, but this time using ASM storage. We've been at the "cataloged datafile copy" stage of things for quite some time. If the RMAN log is any indicator, some datafiles take over 30 minutes to catalog, some take 5.

Back on our 32-bit hardware, this didn't take anywhere near this long.  Can anyone shed some light?

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.


> cataloged datafile copy
> datafile copy filename=/u10/oradata/stage/txbill_idx13.dbf recid=210
> stamp=640430010
> However, each of these take 3-4 minutes, judging by the duplication
> log updates. When I have hundreds of datafiles, 3-4 minutes each is
> an incredibly long time. Nothing is being written to the aux instance
> alert log during this period.
> It seems that since we moved production to 64-bit hardware, this
> duplications went from 9-10 hours (which I thought was way too long)
> to 25-26 hours (which is a horrible joke). I'm going to pour over
> some of the online guides and Robert Freeman's 10g RMAN book. If
> anyone has any tips or cluebats, swing away.

Don Seiler
Received on Fri Dec 28 2007 - 09:30:13 CST

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