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Re: Multiplexing redologs - is there still need for it?

From: Paul Drake <drak0nian_at_yahoo.com>
Date: 12 Mar 2004 23:59:21 -0800
Message-ID: <1ac7c7b3.0403122359.38ae5288@posting.google.com>


"Howard J. Rogers" <hjr_at_dizwell.com> wrote in message news:<40520c09$0$31901$afc38c87_at_news.optusnet.com.au>...
> "Dusan Bolek" <pagesflames_at_usa.net> wrote in message
> news:1e8276d6.0403120815.155dbab6_at_posting.google.com...
> > Today, I have run into an interesting discussion. The question was if
> > there is a need for multiplexing redologs by database (as suggested in
> > Admin manual) if this data are already mirrored (using RAID, disk
> > arrays mirrors, Data Guard, SRDF etc.).
> > I'm somehow paranoid, so I proposed tu use multiplexing, while other
> > party stated that these bytes are already stored on eight different
> > locations. That's sounds sensible, but I remember the issue a long
> > time ago in a company far far away, where one of two multiplexed
> > control files got corrupted and (of course) copies on both mirrored
> > disc vere identical (means corrupted), second redo log on different
> > volume group was OK. So in this case we would been doomed if these
> > redologs weren't multiplexed.
> > What's the opinion on this topic in the newsgroups? Preferably with
> > some technical explanation.
>
>
> Somewhat fascistically, I suspect, but the topic ought not even to be
> discussed. Hardware RAID protects you from hardware failure. It does not and
> cannot protect you from (oracle) software error or (more common) user error.
> Only multiplexing can do that.
>
> Multiplexing should be compulsory. And discussions on whether that's a good
> idea or not ought to be banned.
>
> Regards
> HJR
do you want to rollback to your previous full hot backup ONLY, or do you want to be able to roll forward from that backup set?

IF you want to roll forward, a single log_archive_dest directory is not sufficient.

got the TAR to prove it (but its not public)

Pd Received on Sat Mar 13 2004 - 01:59:21 CST

Original text of this message

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