Oracle FAQ Your Portal to the Oracle Knowledge Grid
HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US
 

Home -> Community -> Mailing Lists -> Oracle-L -> Re: redo log timing

Re: redo log timing

From: Rodd Holman <rodney.holman_at_lodgenet.com>
Date: Tue, 20 Mar 2001 11:00:09 -0800
Message-ID: <F001.002D2105.20010320103200@fatcity.com>

Ian,
This is one of those where you can get the old "it depends" answer. What type of database is this? What level of transaction activity do you have? How big are your redo logs if you switch every 15 min, 20 min, 30 min? How critical is recovery to the current time to you?

If you don't want the overhead of lots of log switches and you can stand to have a possible loss of 30 minutes of data on a recovery then 2/hr would work. (Possiblity of data loss based on losing all logs and mirror logs in a recovery scenario).

Others may have differing opinions on this, but I normally keep mine running in the 15-20 minute range. The overhead difference between 2 switches/hour and 3 or 4 per/hour is generally not noticeable. It makes for smaller archives which makes the gzip of the log run faster and take up less cpu time. (I run a cron job that compresses the archived logs to save disk space).

On Tuesday 20 March 2001 11:36, you wrote:
>
> Now for an Oracle question. It is often touted that redo logs should
> switch every 15 minutes to 30 minutes. Are these the lower and upper
> limits, should the average time to switch logs be within that range, or
> should the median be between that range?
>
> Ian MacGregor
> Stanford Linear Accelerator
> ian_at_slac.stanford.edu
>
>

-- 
Rodd Holman
Oracle DBA
(605) 988-1373
rodney.holman_at_lodgenet.com
Comments made are my own opinions and views. They do not represent views, 
policies, or procedures of LodgeNet Entertainment Corporation
-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.com
-- 
Author: Rodd Holman
  INET: rodney.holman_at_lodgenet.com

Fat City Network Services    -- (858) 538-5051  FAX: (858) 538-5051
San Diego, California        -- Public Internet access / Mailing Lists
--------------------------------------------------------------------
To REMOVE yourself from this mailing list, send an E-Mail message
to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
the message BODY, include a line containing: UNSUB ORACLE-L
(or the name of mailing list you want to be removed from).  You may
also send the HELP command for other information (like subscribing).
Received on Tue Mar 20 2001 - 13:00:09 CST

Original text of this message

HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US