Re: Tom Kyte Availability Option Questions / OPS newbie

From: kg <kg_at_home.com>
Date: Thu, 22 Feb 2001 13:01:40 -0500
Message-ID: <7ucl6.133320$Z2.1771974@nnrp1.uunet.ca>

But remember that a standby is not a complete copy of your original database. There are a few (and only a few!) operations that do not get recorded in the redo logs (no logging bulk loads, create table... as select..., etc )

The dml of these types of operations are not fully recorded in the redo and hence are not replicated to the standaby - they also are not recoverable from your archived redo logs if you do a restoration.

"Mark Townsend" <markbtownsend_at_home.com> wrote in message news:B6B71A4D.3A12%markbtownsend_at_home.com...
> Oracle Parallel Server allows you to run your single database across two
 or
> more machines in a cluster. Hence if one machine fails, the other
 machine(s)
> are still available for use (albeit with twice the workload). I also think
> that the standby database capability in Oracle8i is a better redundancy
> solution than replication - replicating a complete database for redundancy
> is difficult and can introduce significant overhead into your production
> environment.
>
>
>
> > From: Doug C <dcowles_at_i84.net>
> > Organization: Posted via Supernews, http://www.supernews.com
> > Newsgroups: comp.databases.oracle.server
> > Date: Mon, 19 Feb 2001 21:27:52 -0500
> > Subject: Tom Kyte Availability Option Questions / OPS newbie
> >
> > I was looking at an article by Thomas Kyte about the various
 availability
> > options for Oracle, which is at :
> > http://www.oracle.com/oramag/oracle/00-May/o30tom.html
> > but i will sumarize the options.
> > There are 5
> > 1) OPS
> > 2) Replication
> > 3) Standby Database
> > 4) OS- Oriented solutions - such as dual ported RAID devices.
> > 5) Architecture
> >
> > My question revolves exclusively around this comment he makes:
>
> --------------------------------------------------------------------------

---

> > ----------------------
> > "In terms of OPS compared with replication:
> > If failover and availability are the key issues, using OPS wins out in
> > my opinion. If redundancy is the main issue, then using replication is
 the
> > answer (because using OPS is not a redundant solution-you have only one
> > database)."
>
> --------------------------------------------------------------------------

---

> > ----------------------------------
> > Since we have only one database, and that box could crash, how does this
 come
> > in
> > the lead for availability? I can see how one appserver fails over to
> > another,
> > but if there is something wrong with you db server, seems like
 availability is
> > down the drain.
> >
> > Comments, insights?
> > I would pose this to Tom directly, but he is pretty swamped.
> >
> > - D
>
Received on Thu Feb 22 2001 - 12:01:40 CST