High Availability is must for Siebel Production Environment.

As name suggest 'High Availibility' are the sets of all possible solutions to keep enviroment or application up during disasterous situations - say siebel server fails or components crashes or db node fails.

HA solutions could be implememted at each level and there are different ways to do depending upong hardware, OS platform etc. In this topic I would discuss this non-overlooking and very important topis - 'High Availibility'.

To achieve maximal Siebel availability:
1. Deploy the Siebel database in an Oracle Database MAA configuration.
2. Deploy the Siebel application in a Siebel High Availability configuration.
3. Establish a secondary standby Siebel site for disaster recovery, testing and other planned maintenance activities.

Note: In this topic I am assuming Siebel Business Application, Version 8.x and Oracle 11g Db is being used.

To achieve maximum Siebel availability, Oracle recommends deploying Siebel on an Oracle Database MAA foundation that includes the following technologies:
- Oracle Real Application Clusters and Oracle Clusterware
- Oracle Data Guard
- Oracle Flashback
- Oracle Automatic Storage Management
- Oracle Recovery Manager and Oracle Secure Backup
- Oracle Online Upgrade

Oracle Real Application Clusters (RAC) allows the Oracle database to run any packaged or custom application unchanged across a set of clustered nodes. This capability provides the highest levels of availability and the most flexible scalability. If a clustered node fails, the Oracle database will continue running on the surviving nodes.

Oracle Clusterware is a cluster manager that is designed specifically for the Oracle database. In a RAC environment, Oracle Clusterware monitors all Oracle resources (such as database instances and listeners). If a failure occurs, Oracle Clusterware will automatically attempt to restart the failed resource. During outages, Oracle Clusterware relocates the processing performed by the inoperative resource to a backup resource. For example, if a node fails, Oracle Clusterware will relocate database services being used by the application onto a surviving node in the cluster.

Oracle Data Guard provides a comprehensive set of services that create, maintain, manage, and monitor one or more standby databases to enable production Oracle databases to survive failures, disasters, user errors, and data corruption. Data Guard maintains these standby databases as transactionally consistent copies of the production database. If the production database becomes unavailable due to a planned or an unplanned outage, Data Guard can switch any standby database to the production role, thus greatly reducing the application downtime caused by the outage. Data Guard can be used with traditional backup, restore, and clustering solutions to provide a high level of data protection and data availability. Siebel supports both physical and logical standby databases.

Oracle Flashback quickly rewinds an Oracle database, table or transaction to a previous time, to correct any problems caused by logical data corruption or user error. It is like a 'rewind button' for your database. Oracle Flashback is also used to quickly return a previously primary database to standby operation after a Data Guard failover, thus eliminating the need to recopy or re-instantiate the entire database from a backup.

Oracle Automatic Storage Management (ASM) provides a vertically integrated file system and volume manager directly in the Oracle kernel, resulting in:
- Significantly less work to provision database storage
- Higher levels of availability
- Elimination of the expense, installation, and maintenance of specialized storage products
- Unique capabilities for database applications
For optimal performance, ASM spreads files across all available storage. To protect against data loss, ASM extends the concept of SAME (stripe and mirror everything) and adds more flexibility in that it can mirror at the database file level rather than the entire disk level.

Recovery Manager (RMAN) is an Oracle database utility that can back up, restore, and recover database files. It is a feature of the Oracle database and does not require separate installation. RMAN integrates with sessions running on an Oracle database to perform a range of backup and recovery activities, including maintaining a repository of historical data about backups.

Oracle Secure Backup (OSB) is a centralized tape backup management solution providing performant, heterogeneous data protection in distributed UNIX, Linux, Windows, and Network Attached Storage (NAS) environments. By protecting file system and Oracle database data, OSB provides a complete tape backup solution for your IT environment. OSB is tightly integrated with Recovery Manager (RMAN) to provide the media management layer for RMAN.

(I would be covering 'SIEBEL HIGH AVAILABILITY DEPLOYMENT ' later on in continuation...)