Re: Replication Options

The requirments for DR are totaly different from activ/activ replication. We implement DR by the storage replication to remote site. On the remote site we have another machine that is NOT connected to the storage but is built with Oracle software and database defined on the disk on the storage. In case that the primary site falls, you activate the second machine and it uses the database that is on the remote site storage. The replication is performed by the storage controller writing each block to both storage arrays. This option can work fine up to not so remote site.

For active/active you need the machines close by with very high speed connections between them, or the network time will bring the system to its knees.

You need also to decide about syn or asyn replication. While syn replication will cause less overhead it make you dependent on the second site to continue working, asyn replication will cause a lot more overhead in the database (Just think: insert the change into a locat queue, read it and send it to the second machine and then delete it from the local queue).

It also depends on th updates to select ratio. On havily updated systems the penalty will be much worse.

You did not specify what they are doing on the remote site, reporting only or full update application. You did not say what is the distance between them.

To have the users accessing the database from a remote site maybe you can get by with the application running in the remote site and accessing the database in the primary site, or using the web to run the application on the primary site.

As you can see there are a lot of options that must be checked before deciding wich way to go.

Wanting (active/active) and being ready to pay the penalty for this option are two very different things.

Yechiel Adar
Mehish Computer Services
----- Original Message -----
From: <Rajesh.Rao_at_jpmchase.com>
To: <Oracle-L_at_freelists.org>
Sent: Thursday, February 03, 2005 7:29 PM Subject: Replication Options

> Hello All,
>
> We have an application that's presently on 9.2.0.5 on a Solaris 8 box. We
> are looking to have a DR / Standby site for this database at a remote
> location. Logical Standby database and Advanced replication were ruled out
> because of the use of LONG and LONG RAW datatypes, and the use of IOT's by
> the database. So, we decided on a physical standby database.
>
> But now, the requirements change, in that, the user wants a ACTIVE/ACTIVE
> configuration. In all sense, its a RAC database with nodes at different
> physical locations. I read, that 10g supports LONG and LONG RAW datatypes
> for Logical standby.
>
> My questions are:
> 1. Does Oracle support LONG datatypes with Advanced Replications in 10g?
> 2. What options do I have? Any third party applications? (Shareplex?)
>
> Thanks
> Raj
>
>
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