For me, Load balancing is different concept and Failover is different.
Load Balancing is use of improve performance of Application Server in multi app server environment. You can perform load balancing either with software or hardware. It help to distribute request between app server.
If you want High Availability then you should go with some cluster solution where Database and File Server is on a cluster environment with multiple application server so that if any component is down then cluster server can be up.
Attached snapshot may help you to understand it.
docs.xps 988.7 K
can you define what you mean by "HA" ?
what i would consider HA is if one node fails, all work on that node is picked up by other nodes. right now we don't have that - if an appserver fails, any in-progress work on that appserver will fail. you can have multiple appservers in your environment. if one fails the others will continue to work. you can have a cluster for your appserver where one is standby, buy why not just have it be active so it's taking traffic ?
Thanks for the document, it's really helpful.
I understand that I can use Oracle RAC for database server and clustered SAN for file server.
About the HA for application server, I may not understand clearly: i should deploy each job on multiple app servers?
When you have DB in cluster and your app servers will connect to same DB, You do not need to configure any job on MAS, IT will automatically visible to all app servers. So all you need is Cluster DB and File Servers.