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RE: 9i-OCP Question

From: Ron Yount <ronwy_at_swbell.net>
Date: Wed, 30 Jul 2003 18:59:23 -0800
Message-ID: <F001.005C7EC7.20030730185923@fatcity.com>


Well.... Who knows what the author of the question intended, but in the example of 2 (duplexed) redo log groups with archiving, they speak of five disks. One of EACH log member (not shared with log members of another group) and one for the archive log destination.

That being said, I believe the answer to the question is A: 8

Hth,
-Ron-

-----Original Message-----
Jacques Kilchoer
Sent: Wednesday, July 30, 2003 9:19 PM
To: Multiple recipients of list ORACLE-L

> -----Original Message-----
> From: Senthil Kumar [mailto:senthilkumard_at_summitworks.com]
>
> What is the correct answer for this?
>
> Q> If you have 2 redo log groups with 4 members each, how
> many disks does
> Oracle recommend
> to keep the redo log files?
>
> 1. 8
> 2. 2
> 3. 1
> 4. 4

The question specifically says "how many disks does Oracle recommend...?" It seems to me that the correct answer is answer number 4, Oracle recommends 4 disks. (Quote: "When setting up a multiplexed online redo log, place members of a group on different disks. If a single disk fails, then ONLY ONE MEMBER of a group becomes unavailable..." - capitalization mine) Therefore 4 members -> 4 disks.

Here is a link to a relevant section from an Oracle manual.

Oracle9i Database Administrator's Guide, Release 2 (9.2), Part Number A96521-01
Chapter 7 - Managing the Online Redo Log: Placing Online Redo Log Members on Different Disks

http://download-west.oracle.com/docs/cd/B10501_01/server.920/a96521/onlinere do.htm#5414

"Placing Online Redo Log Members on Different Disks When setting up a multiplexed online redo log, place members of a group on different disks. If a single disk fails, then only one member of a group becomes unavailable to LGWR and other members remain accessible to LGWR, so the instance can continue to function.

If you archive the redo log, spread online redo log members across disks to eliminate contention between the LGWR and ARCn background processes. For example, if you have two groups of duplexed online redo log members, place each member on a different disk and set your archiving destination to a fifth disk. Consequently, there is never contention between LGWR (writing to the members) and ARCn (reading the members)."

-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.net
-- 
Author: Jacques Kilchoer
  INET: Jacques.Kilchoer_at_quest.com

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-- 
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Author: Ron Yount
  INET: ronwy_at_swbell.net

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Received on Wed Jul 30 2003 - 21:59:23 CDT

Original text of this message

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