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Oracle RAC [message #74945] Wed, 08 December 2004 03:46 Go to next message
Messages: 2
Registered: December 2004
Junior Member
Hi !

This input only to prevent any decision maker not to believe all what Oracle says about RAC.

RAC will be a very good product when it will be completed. When mounting a RAC database on Oracle Cluster, a lot of things can not be done in the same way than on a "normal" server, mainly due the file system ocfs (utl_file use, hot backup by the OS, use of OS command such as cp ...)

So, prefer a high speed server (4, 8 CPUs) with goods redundant disks associated to a Data Guard system than an Oracle RAC database.

Now, you kown it.



Re: Oracle RAC [message #74947 is a reply to message #74945] Wed, 08 December 2004 05:17 Go to previous messageGo to next message
Mahesh Rajendran
Messages: 10707
Registered: March 2002
Location: oracleDocoVille
Senior Member
Account Moderator
CAN you prove any of your own rhetorics?
OCFS has its own limitations and oracle has admitted it.
RAC is meant for load balancing and transparent failover mechanism.
IT doesnt mean that, moving into RAC will make your application a zillion times faster.
Re: Oracle RAC [message #74949 is a reply to message #74945] Fri, 17 December 2004 01:17 Go to previous message
Michael Hartley
Messages: 110
Registered: December 2004
Location: West Yorkshire, United Ki...
Senior Member


Many of your comments are invalid and the remainder are not relevant.

Firstly OCFS was designed as an alternative to using raw devices for Oracle9i Real Application Clusters (RAC). Management of raw devices is usually a difficult task and many Database Administrators (DBAs) and System Administrators (SAs) are more familiar with filesystems. Another issue with raw devices on Linux is the maximum of 255 raw partitions, as there can be no more than 255 /dev/raw device files.

Though OCFS has not yet been optimized for general purpose applications, the specific optimization for was relatively low number of very large files.

RAC provides vast performance improvements, especially in OLTP environements but also in batch processes environments where all the batch work falls against a single RAC instances. Consider was happens to the database caches when different kinds of work are presented to a single instance.

For a high availability maximum resilient environment, you must consider RAC and Data Guard. If you're platform choice is Linux then you must use OCFS.

I've worked with Oracle database systems for a lot of years, with RAC/DataGuard on Linux being only one of the number of the environments.

Michael Hartley

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