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RE: 9i-OCP Question

From: Jacques Kilchoer <Jacques.Kilchoer_at_quest.com>
Date: Thu, 31 Jul 2003 10:29:23 -0800
Message-ID: <F001.005C8034.20030731102923@fatcity.com>


Except that:
1) five disks was not one of the possible answers, and 2) we don't know that the database is in archivelog mode. For the 9i OCP examination the correct answer is answer number 4 (4 disks). I'm willing to bet on it!

> -----Original Message-----
> From: Ron Yount [mailto:ronwy_at_swbell.net]
>
> 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
>
> -----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/a
> 96521/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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Received on Thu Jul 31 2003 - 13:29:23 CDT

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