Re: Redo + Archive + Data Layout...

From: Howard J. Rogers <hjr_at_dizwell.com>
Date: Tue, 21 Oct 2003 06:04:44 +1000
Message-Id: <3f944060$0$28123$afc38c87@news.optusnet.com.au>

Daniel Morgan wrote:

> Hari Om wrote:
> 

>>I am using Oracle 9.2.0.1 on IBM AIX 5.1L
>>I have come along with the following disk layout for my Database...can
>>anyone point out if there would be any issues:
>>
>>hdisk0(18GB) + hdisk1 (18GB) --> These are MIRRORED. It contains OS +
>>Oracle SW + Control file copy 1
>>
>>hdisk2(36GB) + hdisk3 (36GB) --> These are MULTIPLEXED by Oracle. It
>>contains Redo Logs.
>>
>>hdisk4(36GB) + hdisk5 (36GB) --> These are MULTIPLEXED by Oracle. It
>>contains Archive Destination.
>>
>>hdisk6(36GB) + hdisk7 (36GB) --> These are MIRRORED. It contains
>>SYSTEM Tablespace.
>>
>>hdisk8 + hdisk9 + hdisk10 + hdisk11 + hdisk12 + hdisk13 --> Each are
>>72 GB. These are MIRRORED and STRIPPED (1+0)--> These contain Oracle
>>DATA fiels + Control File copy
>>
>>Can anyone point out any issues in the above layout....?
>>Would it fine if we don't MIRROR REdo Logs?
>>
>>THANKS!
>>
>>

> Mirroring something that is already mirrored by Oracle is creating a
> redundant redundancy.
> Given you have 5L I would make sure hdisks8 through 13 are RAW: No file
> system.

Oracle doesn't mirror. It multiplexes. And doing both is highly recommended. Hardware mirroring protects you against hardware failure; Oracle multiplexing protects you against software problems.

And Hari asked this exact same question several weeks ago, and as I told him then, the real problem with this layout is the ridiculous waste of space that is associated with having two 36GB drives storing just the SYSTEM tablespace.

And the other thing I repeatedly told him back when he originally asked was: if he's going to stripe and mirror all his other data files, what makes him think SYSTEM is so special it needs a disk+mirror all of its own?

HJR

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Received on Mon Oct 20 2003 - 15:04:44 CDT