1. Database Installation & Configuration

• Install Oracle Database software.
• Create and configure databases.
• Apply patches, PSU/RU updates, and upgrades.
• Configure listeners and network connectivity.

2. User & Security Management

• Create and manage users, roles, and profiles.
• Grant and revoke privileges.
• Implement password policies.
• Configure auditing and encryption.

3. Backup & Recovery

• Configure and manage RMAN backups.
• Perform database restores and recovery.
• Test disaster recovery procedures.
• Manage archived redo logs.

4. Performance Monitoring & Tuning

• Monitor CPU, memory, I/O, and SQL performance.
• Analyze AWR (Automatic Workload Repository) reports.
• Identify slow-running queries.
• Tune indexes and database parameters.

Tools

• AWR Reports
• ASH (Active Session History)
• ADDM (Automatic Database Diagnostic Monitor)

5. Storage Management

• Create and manage tablespaces.
• Monitor datafile growth.
• Manage ASM (Automatic Storage Management).
• Allocate storage for applications.

6. High Availability Administration

Oracle RAC

• Manage cluster nodes.
• Monitor RAC services.
• Troubleshoot node failures.

Oracle Data Guard

• Configure standby databases.
• Monitor synchronization.
• Perform switchover and failover.

7. Database Monitoring

Regularly monitor:

• Tablespace utilization
• Session activity
• Blocking and locking
• Alert logs
• Listener status

8. Troubleshooting

• Resolve database startup/shutdown issues.
• Investigate performance degradation.
• Fix corruption issues.
• Analyze alert logs and trace files.

Instead of configuring clients with multiple node IPs, they connect using one SCAN name, and Oracle automatically routes connections to the appropriate RAC node.

Benefits:

• Simplifies client configuration
• Provides load balancing
• Supports node additions/removals without client changes
• Improves high availability

How SCAN Works

• Client connects to SCAN name.
• DNS resolves the SCAN name to one of the SCAN IPs.
• SCAN Listener receives the request.
• SCAN Listener redirects the client to the least-loaded RAC node.
• Client establishes a connection with that node's local listener.

SCAN Requirements

Oracle recommends:

• 1 SCAN Name
• 3 SCAN IP Addresses (for redundancy)

Advantages of SCAN

• Single connection string for applications
• Automatic load balancing
• Easier RAC administration
• Supports cluster expansion without application changes
• Improved failover capabilities

In a RAC environment:

• One database
• Multiple instances
• Multiple servers (nodes)
• Shared storage

This provides:

• High Availability – if one node fails, other nodes continue serving users.
• Load Balancing – user connections can be distributed across nodes.
• Scalability – add more nodes to increase database processing capacity.

Key Components

1. Oracle Instance

Each node has its own:

• SGA (System Global Area)
• Background Processes (PMON, SMON, DBWn, LGWR)

2. Shared Storage

All RAC nodes access the same:

• Data Files
• Control Files
• Redo Logs (configured for RAC)

3. Clusterware

Oracle Clusterware:

• Monitors node health
• Manages cluster resources
• Handles failover

4. Interconnect

A private high-speed network between RAC nodes used for:

• Cache synchronization
• Cluster communication

How RAC Works

Suppose:

• Node 1 and Node 2 are active.
• Users connect through SCAN listeners.
• Sessions are distributed across nodes.

If Node 1 fails:

• Node 2 continues processing.
• Connected applications can reconnect automatically (depending on configuration).
• Database remains available.

RAC vs Single Instance

Asterisk turns a computer into a PBX (Private Branch Exchange)—basically a phone system for businesses or individuals. It lets you:

• Make and receive calls over the internet (VoIP)
• Set up extensions (like office phone numbers)
• Create voicemail systems
• Build interactive voice menus (“Press 1 for sales…”)
• Route calls automatically

Key features

• Voice over IP (VoIP) support
• Call recording
• Conferencing (group calls)
• IVR (interactive voice response)
• Integration with other apps (CRM systems, databases)