Fwd: Status of online redo logs on the standby database

  • From: Christopher Reeve <topher_reeve@xxxxxx>
  • To: oracle-L@xxxxxxxxxxxxx
  • Date: Wed, 20 Jan 2010 06:10:59 -0700

Maybe you can't CC the list?

Begin forwarded message:


From: Christopher Reeve <topher_reeve@xxxxxx>
Date: January 18, 2010 9:52:00 AM MST
To: Laimutis.Nedzinskas@xxxxxx
Cc: oracle-L@xxxxxxxxxxxxx
Subject: Re: Status of online redo logs on the standby database
Yes, I've gone through both documents pretty thoroughly, and I have set the various parameters suggested in both. I don't have network issues. The ONLY busy part of the box is the disk. The standby database generates the logs at the same rate primary does. However, it is log application that begins to lag. My question is really about the status of online redo logs on the standby database when standby redo logs are in use... Thank you for your input though. 

Regards,
Topher

On Jan 18, 2010, at 1:21 AM, Laimutis.Nedzinskas@xxxxxx wrote:


You obviously went over this, didn't you:

http://www.oracle.com/technology/deploy/availability/pdf/MAA_WP_10gR2_RecoveryBestPractices.pdf

http://www.oracle.com/technology/deploy/availability/pdf/MAA_WP_10gR2_DataGuardNetworkBestPractices.pdf

?

from all that reading I got this bottom line:

Tune I/O subsystem, including some kernel parameters tweaking and


PARALLEL_EXECUTION_MESSAGE_SIZE = 64K
I personally set PARALLEL_EXECUTION_MESSAGE_SIZE = 64K by default on all 
databases that have plenty of RAM.
Plus we had to tune SQLnet and TCP/IP related stuff cause LN.... waits were 
taking their share.










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           Christopher Reeve
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Subject Status of online redo logs on the 
           2010.01.17 17:02          standby database


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Hello listers
My first post...
I have a data guard environment running on 10.2.0.4 on solaris 64. I have had some performance issues, on the standby side of things, concerning the rate at which redo is getting applied. Except for the disk subsystem, the 
box itself is bored.  So I'm trying to figure out how to reduce the
physical I/O. The environment itself is managed by the DG broker, and I have it set up to do real time apply, which works great most of the time, until we get to our batch processing periods, four times a month, then the standby begins to lag. One way of reducing I/O, I have read, is to NOT multiplex the standby redo logs. Certainly makes sense, with all the ways of getting redo over. While that did improve performance and reduce I/O, 
I'm still experiencing periods of lag.  Is that enough background
information?  OK, on to the question...
With my situation, real-time apply, etc., I expected to see activity in v $standby_log, which I do. But I didn't expect to see activity in v $log, 
which I do.  I have not seen any status here besides "CLEARING" and
"CLEARING_CURRENT". So is this normal? If not, is this causing additional 
I/O that I can reduce further?

Thanks,
Topher
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