Load balancing / fail over

Question

Dear forum,
Is there an other and more simple / "cheaper" way for load balancing / fail over then using RAC ? E.g. starting more instances againts the (same) database ?
Thanks in advance,
Michel
Edited by: Michel77 on Dec 9, 2008 12:06 PM

Answer 1

The answer would be highly platform and version dependent.
On several platforms you have software implementing a 'shared nothing cluster'. This means you failover complete services to a second server, which is usually dormant.
There is HP Service Guard, Suncluster, IBM HACMP, and Microsoft cluster, which are or can be configured as shared nothing clusters.
For Microsoft there was or is, depending on version, Oracle Failsafe, on top of a MS Cluster.
RAC can be configured in a shared nothing mode too. RAC itself is essentially active/active.
On the other side, you can of course buy a second server, and use Dataguard to set up a standby database.
For a physical standby database, which isn't enabled for more than 10 days, you don't pay a license.
Setting up multiple instances on a single server is obviously not going to work. Those instances need to coordinate what they are doing. This is essentially the task of RAC.
Hth
Sybrand Bakker
Senior Oracle DBA