Re: backup versus export of db

Blair Wheadon (wheadonb_at_cadvision.com) wrote: : In article <4884rs$65r_at_earth.alpha.net>, : metco_at_earth.execpc.com (Milwaukee Tool) says:  

: >I've been told by a Value-Added-Resaler of Oracle that if i want to backup
: >an oracle 7 db, i should first do a full export, and then backup up the
: >exported file.
: >They said that a simple backup of the files used by oracle isn't good enough.

[Snip]

Change your VAR - they're clearly ignorant or at least oversimplifying.

: A normal file-system backup will only work if you shutdown your database.  
: If your database  is running, and you also run a backup, you are risking 
: the referential integrity of the database.  

[Snip]

May I make the following comments ?

1. A Database Export is valuable in that it will check internal consistency of the database, not just ensure that the data files etc can be read. It also allows parts of the data to be restored (individual tables) UNLESS run with a specific option (manuals not to hand), it can also suffer from referential integrity problems. It is unsuitable as the basis of a rollforward recovery.
2. Offline backups are easy - close down the database, backup all data files, online redo logs and at least one control file.
3. Online backups are more complex, but DO work (in my experience). I'm not going to post detailed instructions (as I'd be bound to miss something out and get flamed for it :-) ). Read the manuals and (yet another plug for) "The Oracle DBA Handbook" by Kevin Loney (Published by ORACLE Press).

I'm probably on the verge of a flame - can I point out that ORACLE database administration is not simple, and that it behoves people to be properly prepared ?

That means one or more of :-

	having access to the manuals and having some idea of their contents, 
	buying Loney's book 
	taking some good quality training (not necessarily from me <*g*>)

--
Mark Bluemel	Unix/Oracle Trainer and Consultant
		My opinions are my own, but I'll share them
		All solutions to problems are offered "as is"
		and without warranty - you have been warned :-)