Re: Turn Off Redo Logs?

Paul Bennett <bennett_at_cc.gatech.edu> seems to have written:
>Is there a way to turn off the redo logs?

No.

>The nightly backup of the database here is good enough incase of
>failure.

The online redo logs are used for instance recovery - any event which makes the instance processes disappear without writing all unchanged blocks to datafiles and exiting cleanly requires instance recovery. Without the online redo logs all you have to do is turn off the power during a data-write operation to fuck your db. That's why they're there, and why you can't get rid of them.

You can stop archiving the redo logs, if you don't want to be able to perform media recovery. This shouldn't give you much of a performance increase as you're only saving the resources required to copy a redo log to a different disc every time there's a log switch.

>Also, what is the rule of thumb for size and number of redo logs?

Size: such that log switches occur at a rate you're comfortable with, and are a size that can be handled easily by whatever offline archive storage medium you're using.

Number: You can't have less than two groups, and you should always mirror them across devices, so four is the minimum. If you're using archivelog mode you should have at least three groups in case the log-writer falls behind for some reason.

-michael

-- 
St michael (mainly) Erroneous   http://goliath.mersinet.co.uk/~ishamael/
 "SQL-PLUS> select meaning from my_life where personality is not null;
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