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Re: The old raw devices chestnut.

From: Andy Kent <>
Date: 14 Apr 2004 06:33:43 -0700
Message-ID: <>

From what I remember of Oracle's "basic" backup tool (and I haven't had much to do with it since 8.1.6) you have to put tablespaces (equivalent to our dbspaces) into "backup mode" before you can back them up which means they can't be written to. It's also typical to do all this one tablespace at a time. If my memory is serving me correctly (and I'm quite open to being told it isn't) this is a vastly more primitive mechanism than either ontape or onbar.

Has the basic backup tool moved on since then, and does RMAN avoid any such limitations?

(Sorry to drift off-topic but it's always useful to know what else is out there. Hell, I might need a job with that stuff some day.)


"Howard J. Rogers" <> wrote in message news:<407ce550$0$14771$>...
> Andrew Hamm wrote:
> [snip]
> > ok - I've heard that Oracle has a "variety" of backup procedures, some of
> > them home-cooked, some of them tools you have to pay for. In that case, you
> > would need suitable tools to manage the objects. With Informix, it's shipped
> > with one (now two) tools that perform complete, live, point-in-time archives
> > along with continuous storage of logical logs. Any timestamps etc that need
> > touching are self-contained within the engine spaces, so it's completely
> > unnecessary and almost certainly destructive to do anything with informix
> > spaces apart from via the utilities provided.
> [snip]
> For many aeons, it has been this on Oracle. Shell-scripted backups,
> with commands provided by the database to make the O/S-produced backup
> recoverable and usable. But since version 8.0 (and we've had 8.1.5,
> 8.1.6, 8.1.7, 9.0.1, 9.2, and 10g since then), Oracle has provided RMAN
> -for free- which does cleverer and safer backups than any shell script
> could manage. It's a command-line tool for the scripting addicts, but
> has a GUI front-end for those so inclined. Works very nicely.
> The emphasis is very much on using RMAN these days (when first released
> it was a bit rough round the edges!), and O/S-based backups are
> gradually becoming a thing of the past, or at least not too well looked
> upon, generally (though it's nice to have the choice).
> Point is, given the context of this discussion, RMAN works just as well
> with raw devices as it does with file systems, and will happily backup a
> raw-based database onto a file system, or vice versa.
> Raw isn't the utterly inflexible nightmare in Oracle it's sometimes made
> out to be.
> Regards
Received on Wed Apr 14 2004 - 08:33:43 CDT

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