So what is Oracle Real Application Clusters??

From some time i was thinking of writing about some basic stuff regarding RAC.
RAC stands for Real Application Cluster , which in plain term means a Database working in Cluster mode,now hope most of you are familier with the term CLUSTER, otherwie just do a google, am sure you will find good pages on this. Since this database works in cluster minimum of 2 nodes are required to operate. So what benefits does this provides!! First of all RAC is an active-active cluster, this means both the nodes of Oracle cluster can access the database simultaneously.Hence in the event of failure if one node goes down, the database can still be accessed from the second node. So you can give 99% uptime..:-)
Second benefit is that it also provides for feature such as load balancing, in this case if we have 4000 users accessing a database, they will be evenly distributed on both the nodes, i.e 2000 users on each node. This helps in utilizing system resources of both the nodes and also easing of CPU utilization. In some other post i will surely write about some really good scenario that i have come across in the environments i have managed..and will also try to explain more about RAC..