Home » RDBMS Server » Backup & Recovery » Online Redo - Different Destination (Windows XP / Oracle 11g Home)
Online Redo - Different Destination [message #590205] Mon, 15 July 2013 15:29 Go to next message
Sham.Afrith
Messages: 11
Registered: May 2013
Location: India
Junior Member
hi ,

As you known i am new to oracle. I would like to know that process of redo logs by LGWR.

i already have 3 redo log groups and their status are

SQL > select group#, status from v$log;

GROUP# STATUS
------ ------
1 INACTIVE
2 INACTIVE
3 CURRENT

i added new log group as 4 to new destination path. the new path is different disk (external Hard disk ). Because of production as policy followed "Multiplexing redo".

SQL > ALTER DATABASE add logfile group 4
('h:\orcl\redobackup\redo04a.log', 'h:\orcl\redobackup\redo04b.log')
size 100m;

after altered the database i got another group and that status follows

GROUP# STATUS
------ ------
1 INACTIVE
2 INACTIVE
3 CURRENT
4 UNUSED

now my doubt is exactly this. All the tiny transactions by the database is written to online redo. but my new redo log file group is still UNUSED, that meant that is ready to use. if i lost my first 3 redo online files then how i will get recover from the 4 redo group ?

thanks is advance
Re: Online Redo - Different Destination [message #590210 is a reply to message #590205] Mon, 15 July 2013 16:38 Go to previous messageGo to next message
John Watson
Messages: 4508
Registered: January 2010
Location: Global Village
Senior Member
You have misunderstood the concept of "multiplexing". It means that different members of the same group should be on different devices, so if you lose one device the other member will still be available.
Re: Online Redo - Different Destination [message #590226 is a reply to message #590205] Tue, 16 July 2013 00:10 Go to previous message
Michel Cadot
Messages: 58913
Registered: March 2007
Location: Nanterre, France, http://...
Senior Member
Account Moderator
All these kinds of question are answered in Database Concepts.

Regards
Michel
Previous Topic: rman restore
Next Topic: Delete Obsolete backup from RMAN
Goto Forum:
  


Current Time: Wed Aug 27 18:30:11 CDT 2014

Total time taken to generate the page: 0.13608 seconds