Re: Mirrored disks Vs duplexed logs

krader_at_crg8.sequent.com (Kurtis D. Rader) wrote:

>jared_at_psnw.com (Jared Still) writes:
 

>>Deleting a tablespace data file is an error that can be recovered from
>>without data loss.
 

>>Deleting a unarchived non-mirrored redo log file _will_ result in
>>data loss.
 

>So will deleting a tablespace data file. What do you think happens to
>the in progress, uncommitted transactions when the tablespace is taken
>offline due to an error writing to a data file? What will it cost to
>restart those transactions? What about the cost to the business of lost
>productivity, sales, etc. while the tablespace is being recovered?
>What about the application which has commited data even though its
>"transaction" is not complete? How difficult will it be to cleanup and
>restart that application?
 

>Almost any database recovery will be costly for the business. Certainly
>mirrored redo logs will minimize the cost and pain and provide valuable
>protection against system failures. But I still maintain that it is silly
>to consider this feature as providing protection against incompetency.
 

>--
>Kurtis D. Rader, Senior Consultant krader_at_sequent.com (email)
>Sequent Computer Systems +1 503/578-3714 (voice) +65 223-5116 (fax)
>80 Robinson Road, #18-03 Currently on assignment in the
>Singapore, 0106 Asia-Pacific region

Losing a non-mirrored redo log requires database media recovery. Losing a datafile in a tablespace requires datafile or tablespace recovery.

Big difference.

Jared Still, Oracle DBA
RxNet, Division of Value Health
"All opinions are mine, no one else wants them" jared_at_psnw.com Received on Wed Jul 17 1996 - 00:00:00 CEST