----- Original Message -----
From: "Tim Schaefer" <tim@spamethnot.com>
To: <informix-list@iiug.org>
Sent: Wednesday, February 11, 2004 9:15 AM
Subject: Re: Whatcha' wanta have?????


> Mark,
>
> I don't know Oracle well enough to talk competently about redo logs,
> but it's my limited understanding they are a bit different than the
> logical logs in Informix. As I understand it Oracle people live and
> die with creative log shipping that most Informix people would never
> even think of doing with logical logs. This is a good thing about
> Oracle, as I understand it, but the comparison is not quite apples
> to apples.

-- slightly OT, but of interest (at least to me)

I was just reading something about this today. They have an undo log -
which is analoguous to our physical log, and a redo log which is analoguous
to our logical log (did I miss a third one here?). Something cute that they
do is allow you to mirror the logs - set up groups and the engine will write
to all members of the group - all three or 15. We would do the same thing
by mirroring the dbspace or the underlying disk.

Also, evidently their desire for 'cooked' files vs raw disk stems from the
ease of backup. Oracle opts for standard utilities to perform cold backups
(database down during backup) - so just copy the file off. They do support
a hot backup - roughly the same way Informix does, but it looks fairly
complex to set up (and I get a queasy feeling reading the description of
events). They don't have anything to compare to the 'simplicity' of onbar
or ontape.

-- sorry, backups are on my mind right now - amanda is, like, totally cool.
(http://www.amanda.org/)

cheers
j.


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