Re: Oracle database mirroring questions

These are all great questions. I suggest you read the Oracle Concepts manual for starters, then dig deeper into aspects of the architecture you are interested in. Once you understand, at a high level, exactly what you are after, you can narrow your query to the group.

1. yes
2. leave as an exercise
3. more a function of the platform vendor, but yes, Oracle supports it. (RAC)
4. RAC man, RAC, but beware that not all applications will scale nicely
5. RAC/OPS requires RAW disk storage
6. NFS is not for use with Oracle datafiles

-Kevin

"Sony Antony" <sonyantony_at_hotmail.com> wrote in message news:3eb007f1.0304231234.5d190a36_at_posting.google.com...
> We have been looking at the database redundancy problem from a high
> level for architecturing our distributed application. I m not an
> expert in Oracle. So I decided to ask them here before deciding on any
> particular solution.
>
> 1. Does Oracle provide any database replication/mirroring mechanisms,
> so that there will be a warm backup database to take over, if the
> main/primary crashes. If it does what will be the performance hit (
> cpu usage ) on the primary because this duplication mechanism is
> running in the background.
>
> 2. If such a mechanism as above exists, how does it work. Does it
> duplicate only the modifications of the original database. Does it
> locks the whole tables while it is duplicating the data. Or does it
> lock just the rows - in which case the client applications will not
> 'feel' its presence much
>
> 3. Does Oracle provide any clustering mechanisms for fault tolerance,
> wherein N number of machines will all have exactly mirrored databases.
> One can afford to lose a number of its node machines. As long as at
> least one node is up all client applications can run without any
> problems.
>
> 4. Does Oracle provide any clustering mechanisms for load balancing,
> wherein data will not only duplicated among the nodes as 3. above, but
> different clients can connect to different node machines in a load
> balancing fashion, and they will all see the exact same data.
>
> 5. I was of the understanding that Oracle uses raw disk space. IOW in
> the case of Solaris, it doesn t use the default Solaris UFS file
> system, but uses raw disk space with indexing etc implemented with
> respect to the physical disk location. This makes disk access faster.
> Did I get this wrong. Or is there an option to do it on top of the
> file system or as a raw file system.
>
> 6. One of the possibilities we thought about so as to implement a
> clustering, was to have an NFS server, whose disks are mounted in a
> number of different machines. Each of these machines will run an
> Oracle database server, but accessing the same NFS mounted database.
> Is this possible. I personally didn t think so since if multiple
> machines are modifying the same data at the same time, this will
> result in data corruption, since each machine's modification might not
> be inside a single atomic write() system call.
>
>
> Thanks a lot for reading.
> --sony
Received on Thu Apr 24 2003 - 08:32:58 CDT