RE: Questions on ASM best practices
Date: Tue, 16 Dec 2014 16:26:36 +0000
Message-ID: <4AF37DF85FABC641A090D23044A9C9B483DBC451_at_EXMBWLM01.TRAVELCLICK.NET>
Typically we create separate disk groups for each database so we can allocate required space to each database and when database is dropped, we can drop the disk group.
From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Ls Cheng
Sent: Tuesday, December 16, 2014 11:23 AM
To: Hameed, Amir
Cc: oracle-l_at_freelists.org
Subject: Re: Questions on ASM best practices
Hi
You can create two disk groups, data and fra and place one member in each disk group Regarding a ew disk groups per DB. I only do that when I have to snapshot the disks, seperate each DB in their own disk groups otherwise just use a couple of disk groups. Regards
On Tue, Dec 16, 2014 at 4:17 PM, Hameed, Amir <Amir.Hameed_at_xerox.com<mailto:Amir.Hameed_at_xerox.com>> wrote:
Hi folks,
I am in the process of implementing ASM for the first time. I have a few questions that I would like to ask regarding ASM best practices for both single instance and RAC databases. The Grid/ASM version is 12.1.0.2<http://12.1.0.2>:
• Redo log file placement – In the non-ASM world, I am used to using two groups for redo logs on multiple mount points with multiple log members in each group. How does this change in ASM? For an externally-managed ASM disk group, should there be multiple ASM redo disk groups with each hosting a redo log group or should one ASM redo disk group with multiple members be sufficient?
• Managing multiple databases – In the non-ASM world, we allocate a separate set of mount points for each database that we set up. This isolates an environment at the storage level and also enables us to take storage-based snapshots of a database file systems for backup. Restore is also simple and quick where we restore from the online snaps. What is the best approach to manage multiple databases in ASM? Should each DB have its own set of ASM disk groups or should all databases be placed in the same set of disk groups? For example, for databases with SIDs ABCD, MNOP & WXYZ:
o Should there be only one set of ASM disk group (DATA, REDO, RECO, etc.) for all of the above databases OR
o Should ABCD be in its own set of disk group (DATA_ABCD, REDO_ABCD, RECO_ABCO), WXYZ be in its set of disk group (DATA_WXYZ, REDO_ WXYZ, RECO_ WXYZ), etc.? This model seems to give more flexibility in terms of retiring an environment where a DG could just be dropped and a new one created when setting up a new environment, either via cloning or creating one from scratch.
• AU and stripe sizes – For an Oracle E-Business Suite type system, which is hybrid in nature, should the AU size be 1M for the DATA and REDO groups? Should the stripe size be 1M and 128k for DATA and REDO groups respectively?
Any feedback will be appreciated.
Thanks,
Amir
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