Re: Tuning RMAN backup and recovery

  • From: "Don Seiler" <don@xxxxxxxxx>
  • To: oracle-l <oracle-l@xxxxxxxxxxxxx>
  • Date: Fri, 28 Dec 2007 09:30:13 -0600

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.

Don.

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