Re: Separate ASM disk group for online redo log files?

From: Mark D Powell <>
Date: Mon, 11 Apr 2011 07:52:46 -0700 (PDT)
Message-ID: <>

On Apr 11, 4:05 am, mhoys <> wrote:
> Ok, I've read a lot about ASM recently :-)
> In one of the technical papers from Oracle, they recommend to have
> only 2 disk groups: one for the data files, and one for the recovery
> files (FRA). This means that the online redo log files are included in
> the disk group for the data files, but I wonder if this is a set-up
> that is followed by most DBA's? I would think that, for performance
> reasons, it's best to create a separate third disk group for the
> online redo log files? How do you guys do it? :-)
> Thanks,
> Matthias

Matthias, I think the answer depends on preference and if you underlying logical disks that you assign to the disk group are separate physical disks or just different logical disk spread across the same physical disks for both diskgroups.

When the physical disks are the same and the physical disk stripe size is the same there shouldn't be an IO benefit from separating the two via ASM. Most disks assigned to ASM are logical disks and it is how the logical disks are defined that really controls the IO performance.

HTH -- Mark D Powell -- Received on Mon Apr 11 2011 - 09:52:46 CDT

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