Re: Redo Log Question

From: Bruno Jargot <see_at_reply.to.invalid>
Date: Tue, 24 Dec 2002 10:47:36 +0100
Message-ID: <s3bg0v42ab06s5q38i1rtmquki70nv8t0j@4ax.com>

On 23 Dec 2002 00:57:51 -0800, Burt wrote:

>Uhh ? Why wouldn't Oracle put the same damn corruption in both
>copies? It did it to me once in version 7.3.2.3 and I spent the next
>27 hours recovering. Corruption got in the datafile and REDO logs and
>was also archived. We (myself and an Oracle analyst at Oracle support)
>didn't know for sure when the corruption occurred. Got lucky doing a
>point-in-time recovery with a guess.

I don't think multiplexing redolog help against corrupted archivelog.

When archiving redolog (single destination), only one member will by archived. If a corruption by LGWR occured, there is 1/2 chance that the corrupt redolog is archived and as there are 2 writes instead of one (2 more chances to have a corrupted redo log), the risk of having corrupted archivelog with multiplexed redolog or with no multiplexed redolog is the same.

So multiplexing helps against corruption in active redo logs but not in archived logs. Received on Tue Dec 24 2002 - 03:47:36 CST