Oracle-L: Re: 9i-OCP Question

From: Tim Gorman <tim_at_sagelogix.com>
Date: Mon, 04 Aug 2003 10:04:34 -0800
Message-ID: <F001.005C8D63.20030804100434@fatcity.com>

Unless ordering superannuated storage from eBay, disks are sized at either 36Gb, 73Gb, or larger. Dedicating these devices to online redo log files of size 100Mb, 500Mb, or 1Gb might be tough to get past the CFO.

The CIO/CTO might well also ask why some form of RAID-1 or RAID-5 redundancy is not recommended for use here. What would that reality do for the answer to this question? Especially if RAID-5 is in use (yes, BAARF)! Steve's answer of 42 would be closer to the mark than any answer yet provided, besides being celestially correct...

Also, we're talking about a single process named LGWR and another 1-2 processes named ARCn. Isn't it possible that these storage devices can handle occasional concurrency of 2-3 without degrading performance? Yup, the answer is "it depends", not "A", or "B", or "C"....

Whatever "Oracle's recommendation" is for this question, it is certainly a tad on the simplistic side and useless in real life. The discussion is certainly worthwhile, but as a multiple-choice question with only one answer it is worthless. The OCP exam does not deal in reasoning and discussion...

on 7/30/03 12:34 PM, Igor Neyman at ineyman_at_perceptron.com wrote:

> Well, in archivelog mode LogWriter may use one group and Archiver may
> use the other group, so I'd agree with Kirti.
> 
> Igor Neyman, OCP DBA
> ineyman_at_perceptron.com
> 
> 
> 
> -----Original Message-----
> Mladen Gogala
> Sent: Wednesday, July 30, 2003 12:59 PM
> To: Multiple recipients of list ORACLE-L
> 
> There are two reasons:
> 1) Redo log groups are never used simultaneously, so they can reside on
>   the same disk. Log members should not be on the same disks for
> increased
>   survivability. That gives us 2 groups with 4 members, each two
> members
>   sharing the same device - 4 disks alltogether.
> 2) It's because I say so and I'm an 8i OCP.
> 
> 
> On 2003.07.30 13:44, KENNETH JANUSZ wrote:
>> Why?  What is the logic?
>> 
>> Ken Janusz, CPIM
>> 
>> ----- Original Message -----
>> To: "Multiple recipients of list ORACLE-L" <ORACLE-L_at_fatcity.com>
>> Sent: Wednesday, July 30, 2003 12:29 PM
>> 
>> 
>>> The answer is 4. Of course, no one in the right mind would have
>>> 2 groups with 4 members each.
>>> 
>>> On 2003.07.30 13:19, Senthil Kumar wrote:

>>>> Hi all,
>>>>
>>>> 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
>>>>
>>>> Which is the correct answer.
>>>>
>>>> TIA
>>>> Senthil
>>>>
>>>> --
>>>> Please see the official ORACLE-L FAQ: http://www.orafaq.net
>>>> --
>>>> Author: Senthil Kumar
>>>> INET: senthilkumard_at_summitworks.com
>>>>
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>>> 
>>> --
>>> Mladen Gogala
>>> Oracle DBA
>>> --
>>> Please see the official ORACLE-L FAQ: http://www.orafaq.net
>>> --
>>> Author: Mladen Gogala
>>>   INET: mgogala_at_adelphia.net
>>> 
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>> 
>> --
>> Please see the official ORACLE-L FAQ: http://www.orafaq.net
>> --
>> Author: KENNETH JANUSZ
>>   INET: kjanusz_at_att.net
>> 
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-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.net
-- 
Author: Tim Gorman
  INET: tim_at_sagelogix.com

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Received on Mon Aug 04 2003 - 13:04:34 CDT