FAQ
Here is an example form one of my standby databases
GROUP#,DBID,THREAD#,SEQUENCE#,BYTES,USED,ARCHIVED,STATUS,FIRST_CHANGE#,FIRST_TIME,LAST_CHANGE#,LAST_TIME

5,2993939164,1,539739,1258291200,512,YES,ACTIVE,124541122419,4/5/2009 11:15:20 AM,124541122522,4/5/2009 11:15:20 AM
6,2993939164,1,539738,1258291200,294810112,NO,ACTIVE,124540991837,4/5/2009 11:03:59 AM,124541122419,4/5/2009 11:15:20 AM
7,UNASSIGNED,1,0,1258291200,512,NO,UNASSIGNED,0,,0,
8,UNASSIGNED,1,0,1258291200,512,NO,UNASSIGNED,0,,0,
9,UNASSIGNED,1,0,1258291200,512,NO,UNASSIGNED,0,,0,

As you can see both are active but one is archived=yes the other is not sicne it is a realtime recieve . in a very busy environment you will see all unassigned as Active with one being used as realtime till time that the backlog is more than the standby redo logs.

Original Message ----
From: Yong Huang
To: john.hallas_at_morrisonsplc.co.uk; fuadar_at_yahoo.com; Martin Brown
Cc: oracle-l@freelists.org
Sent: Sunday, April 5, 2009 9:39:09 AM
Subject: RE: Why extra standby redo log group?

Martin, John, Fuad,

Thank you. When you have heavy transaction for a period of time, if you have n log groups on primary and n+1 SRL groups on standby, do you see all n+1 SRL groups used? That is, on the standby, do you see all, not just n, rows in v$standby_log under status column, alternately showing 'ACTIVE'?

I know if I manually switch logfile on primary, only n SRL groups will be 'ACTIVE' (the extra stays unused). I'll test by building a small data guard where primary is on a node with fast storage and standby with slow storage and create lots of redo.

Yong Huang

On Sun, 4/5/09, Martin Brown wrote:

From: Martin Brown
Subject: RE: Why extra standby redo log group?
To: john.hallas_at_morrisonsplc.co.uk, fuadar_at_yahoo.com, yong321_at_yahoo.com
Cc: oracle-l@freelists.org
Date: Sunday, April 5, 2009, 8:46 AM

Totally agree. Our configuration has 8 primary nodes and (of
course) only 1 standby node. For those that don't run
DataGuard 10g, you can only have 1 active standby node.
Normal log switches happen about 3 per hour. During peak
times, our log switchs pick up speed and this configuration
keeps up quite nicely.
From: John.Hallas_at_morrisonsplc.co.uk
To: fuadar_at_yahoo.com; yong321_at_yahoo.com
CC: oracle-l@freelists.org
Date: Sun, 5 Apr 2009 14:33:16 +0100
Subject: RE: Why extra standby redo log group?

I would agree with what Fuad says, it is to ensure
that the standby can keep up with the primary. It is only a
recommendation though and not mandatory
John

-----Original Message-----
From: oracle-l-bounce_at_freelists.org
On Behalf Of Fuad
Arshad
Sent: 04 April 2009 03:44
To: yong321_at_yahoo.com
Cc: oracle-l@freelists.org
Subject: Re: Why extra standby redo log group?


Well in my case I've seem standby redo logs used
to cover for backlogs I.e Log switching is faster than the
standby instance can perform

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