Re: High Availability Requirements/Concepts

Gump wrote:
<snip>
> R4. We must be able to manually turn off the "synchronisation"
between
> the two sites to allow the database at the secondary site to become a
> test environment. It is acceptable in this circumstance that the
> primary site does not have a standby site for unplanned outages.
>
> My investigation of many discussions, oracle documents and metalink
> posts shows there are different ways to achieve the above but I am
> unsure about the following:
>
> Q1. Can R4 (above) be met if using Oracle Data Guard? That is, can
you
> turn a standby database into a test database that can operate
> independantly to the production database?

Yes, by breaking the standby.

> Q2. Following on from Q1, is the standby database rebuilt from a
backup
> of production after you have finished testing?

Yes.

So yes, DataGuard can fulfill all your requirements.

R4 is very curious though, you obviously have data that you really, really care about as both the primary and the standby are clustered (in addition to you actually having a standby in the first place). R4 states - sometime we don't care (or more strictly are prepared to risk) losing all our data permanently. - It sort of begs the question under what circumstances are you prepared to tolerate loss of the datacentre.

Dan's point about licensing is worth bearing in mind as well, if you are using the db for test rather than opening the standby as a reporting db then you might well find you need a full license for it.

Niall Litchfield
Oracle DBA
http://www.niall.litchfield.dial.pipex.com Received on Mon Apr 04 2005 - 03:52:15 CDT