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Re: Question of degrees in Oracle DB recovery

From: Daniel Fink <Daniel.Fink_at_Sun.COM>
Date: Tue, 29 Jun 2004 10:52:31 -0600
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O Great And Mighty Tim, I must humbly disagree in a groveling manner. </humor>

Nothing can be considered recoverable until it can be *read* from tape. At a recent IOUG, we were discussing B&R and one of the folks told a story about a tape drive where the head was moving a fraction of a millimeter (or so) every time a tape was inserted. As the writing worked like a charm (no errors) they did not worry about it. When it came time to read the tape, guess what...they couldn't. Nice backups, too bad they could not be used for recovery.

 From personal experience, one client I worked with was writing corrupted archived redo logs to tape every night. Of course, the logs could be restored from tape...but they were useless.

This is not to say that you have to test every tape by performing a recovery. But it is a good idea to make sure at least some of the tape can be read and use old tapes to perform recoveries when possible. One good opportunity is when development/test/qa wants a copy of production to use. Instead of exp/imp, take a little time and rebuild the database through recovery. Might take a little extra time (might not, depending on the amount of data to be retrieved), but you will have some confidence in the backup integrity.

Daniel Fink

Tim Gorman wrote:
> Stephen,
> One good rule of thumb is that nothing can be considered recoverable until
> it is copied to tape, at least once.

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Received on Tue Jun 29 2004 - 11:50:01 CDT

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