RE: Mirroring redo log groups or not ?

  • From: "Vishal Gupta" <vishal@xxxxxxxxxxxxxxx>
  • To: <tim@xxxxxxxxx>, <hkchital@xxxxxxxxxxxxxx>
  • Date: Wed, 8 Apr 2009 10:19:04 +0100

I would expect any sysadmin worth their money to search for files based on 
modification time rather creation time. And for an active database online redo 
log will always have the modification time of today.
But yes, there is are people who may consider even log files to be useless. But 
in my opinion log files should not be simply deleted. Rather log files older 
than certain date should be deleted. As log contain lot of important 
troubleshooting information when investigating a problem which occured sometime 
in past.
Vishal Gupta   


From: oracle-l-bounce@xxxxxxxxxxxxx on behalf of Tim Gorman
Sent: Wed 08/04/2009 00:51
To: hkchital@xxxxxxxxxxxxxx
Cc: mwf@xxxxxxxx; david.barbour1@xxxxxxxxx; Jon.Crisler@xxxxxxx; 'Rajeev 
Prabhakar'; 'Oracle-L Freelists'
Subject: Re: Mirroring redo log groups or not ?

One situation I've witnessed....

A lot of people create the online redo log files with the file-extension
of ".log".  A lot of SysAdmins have a "cron"-initiated script that
removes files named ".txt", ".log", ".lst", etc that are older than N
days old from certain file-systems, or sometimes when a file-system is
filling up someone will run a "find" command to find big text files
(i.e. ".log" is a good candidate) and get rid of them.  Put the two
together and you've got the perfect storm.

For my part, I always use the file-extension of ".rdo" or just plain old
".dbf", but never ".log".  Of course, someone can still remove files
with those extensions, but I feel the probability is smaller...

Tim Gorman
consultant - Evergreen Database Technologies, Inc.
P.O. Box 630791, Highlands Ranch CO  80163-0791
website   =
email     = Tim@xxxxxxxxx
mobile    = +1-303-885-4526
fax       = +1-303-484-3608
Yahoo IM  = tim_evdbt

Hemant K Chitale wrote:
> VERY TRUE.  I've never bought the argument that mirroring online redo logs is 
> a protection from DBA error.
> ---  wrote:
> There is no protocol that can protect you from human error bysomeone with
> authority to remove an online log file.
> <snip>
> --
> //

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