We have been looking at the database redundancy problem from a high
level point of view, for the purpose of architecturing our distributed
application. I m not an expert in Oracle. So I decided to ask them
here before deciding on any particular solution.
- 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.
- 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
- 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.
- 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.
- 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.
- 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 - 07:52:03 CDT
