Re: 2-Phase commit or replication?

One way of dealing with a second copy purely for backup purposes is to have the second database in a constant recovery state (using 'recover until canceled'). Whenever a redo log fills up on the primary site, ship it to the backup site and apply it as part of the recovery. If the primary site fails then all you would need to do is to apply whatever redo log you have left, and bingo.... you're in business!  

This method is a proven, industrial strength method that has been used for a very long time. It requires LESS resources than replication because it doesn't require any additional resources on the primary site other than copying the redo log. However, on the other side the secondary database (backup) is NOT available because it is in constant recovery mode. With replication, this backup system could be used for other things such as reporting, etc.  

Hope this helps.  

Walter Schenk
SoluTech Consulting Received on Thu Jun 01 1995 - 00:00:00 CEST