Real Application Clusters (RAC)

- Clustered database is just like a single database accessed by multiple instances that are running on the server.

- The instances are being run separately or individually on the server pool and when the demands rise they are shifted to acquire more space according to the requirements.

- Clustered database provides dynamic access to the database and on the demand of additional resources they are added to the server pool.

- If one cluster is taking up the load then that load is shared between other clusters running on the server and the application services are provided in a much faster and better way.

- This also allows the adding of additional resources dynamically to the server pool with no downtime and the application starts running soon it is deployed on the server.

- Cache function is used to show the storage of the information in the clustered network with the Oracle database.

- This uses the database transfer medium and it involves two nodes where one reads the data block from the disk and another write the data to the same disk.

- It provides very good performance and increases the flexibility in terms of execution of the application that is using the platform.

- RAC uses a dedicated server for its network connection and the cache fusion is an internal part to the cluster.

- It uses the same database and keeps the things in the cache till the information is not needed anymore by any other application. It queries the data only when it totally necessary to do it.

- The query from the user always results in the most current version even after the data is being modified.

- Oracle RAC requires an active connection of the network to the LAN (Local Area Network) so that the database server can be found and connected.

- The database server is further having connections with application servers that store the applications and allow user to transfer their data.

- The connection is required with the server pool so that the transfer of services and applications can be done on demand basis.

- The interconnection between the networks is really important as it has to maintain the overall flow of the pools and the resources.

- Oracle RAC provides support to redundant interconnects relatively and it provides an overall infrastructure solution.

- The load balancing and inter-node messaging can be handled more carefully when the networks or the servers are interconnected to each other.

- Oracle Real Application Clusters are the key components of the existing architecture.

- It provides directions and management of the applications that needs to be architect using the architecture.

- It provides high scalability of the applications that is being run on a single server and it takes the advantage of lower cost commodity hardware to reduce the cost.

- It enables the Oracle database to be run and maintained using the business application that are on the server pools and involves packaged products as well.

- It provides a way to integrate the in-house applications that are developed using the oracle database and its technology.

- It allows easy management of the server by providing the ability to remove the server as a single point of failure in the database application environment.

- Oracle Real Application (RAC) provides the interaction of executable file with the Oracle database.

- It allows the running of any packaged or custom built application with the Oracle database that is running on a server pool.

- It provides very high level of availability, flexibility and scalability to run the application and store it to the database.

- It creates the database such that if the pool fails then the database is continued to run from the remaining servers and the load can be distributed.

- It makes it easier for the administrator to maintain many servers at the same time by load-balancing techniques and providing provision to add more and more servers when the load increases.

- Oracle RAC consists of a database that is represented in a clustered manner in the architecture.

- The cluster is the collection or pool of independent servers that make up one single system.

- Cluster architecture provides more flexibility to manage and follow a modular incremental approach to improve the fault errors and provide an incremental system.

- This architecture provides the maximum security in terms of ensuring high availability of the resources to the users.

- It provides the resources on demand and provides hardware architecture such that a single point of failure is being removed.

- The architecture provides the decoupling of the Oracle instance like the process and memory that are running on the server from the Oracle database.

- Oracle Clusterware is a portable solution that comes up with the Oracle database to be used by the application that is being integrated and designed.

- It provides a complete solution of all the clustering problems and supports all the applications that use the functionality of Oracle database.

- It helps in implementation of Oracle RAC and support the clustered database as well that allow more and more applications to run.

- It manages all the Oracle RAC database integrations on the server and system with their statuses and provides an automatic recovery in case of any failure occurs.

- It provides high availability APIs that can be used with the applications and manage to provide a framework that can be integrated and used to develop more applications.

- It allows the user to use the registration services that allow starting, stopping and monitoring of the processes if any failure occurs.

- The Hardware Architecture of the Oracle RAC clusters provides a shared architecture with the server pools and allows all the storage devices to be shared.

- Hardware Architecture supports different types of storage networks like Network attached storage (NAS), Storage Area Network (SAN) and SCSI disks.

- Hardware architecture is such that it provides appropriate choices for the storage pools and system that provides scalability and flexibility to the overall system.

- The architecture should contain the input and output for the application that need to be developed and then the system can have more scalability.

- Hardware architecture supports more application to be added in the server pool and allows better integration of services.

- Oracle uses the UDP over the GigE to interconnect to the cluster and the servers. It makes use of crossover cables to interconnect the database.

- It supports more than one servers connected through LAN connection and shared a pool of storage.

- Oracle Clusterware supports the more than one node in the cluster and it supports the node to be running more than one different operating systems.

- All the servers should support the same architecture and have the same detail information as well. This way the servers need to be in synchronization with each other.

- The servers need to run on a particular node and communicate with other servers that are running on several other nodes.

- The file system and volume management in Oracle RAC should know about the architecture that is being used and it should be aware of the clusters that are involved in it.

- Oracle supports automatic storage management that automates the storing of files and setup the communication in between the databases storage pools.

- Oracle supports the high performance of the input and output of the storage subsystem by providing easy tools to use to maximize it.

- They provide a way to balance the load across the available resources that allows the correct optimization of the file system and volume management.

- Oracle RAC provides dynamic volume manager and it has a file system that contains the information of the cluster file system as well.

- The cluster file system in oracle is called as (OCFS) and it has the connection with the databases that provide raw devices and command line features.

- Oracle RAC is using the virtual IP address for each server that is present in the cluster as it allows easy management of the Oracle Clusterware by taking the subnet as LAN.

- The VIP address is used by the applications and services of the Oracle RAC and then it also helps in connecting it to the Oracle RAC database.

- Virtaul IP addresses keep track of the failures and if one node fails then the load gets shifted to another node that is present in the cluster.

- This provides an easy way to manage the node down response for the incoming connections and provide the requests for that connection.

- It helps in increasing the availability for the services and the applications that takes longer time to run before the request fails.

- It changes the server pool addresses if the connection fails in between while serving any request from any other source.

- Oracle RAC provides this Naming service that provides easiness in scaling up the automation of the VIP management system of the Oracle RAC architecture.

- GNS (Grid Naming Service) has to be maintained and monitored by the Network Administrator to maintain the DNS of the system.

- Virtual IP addresses can be maintained by using the cluster and automation can be made in regards of assigning of the IPs.

- Adding of the servers can take place from the pool when the network administrator returns additional IP addresses and GNS requires DHCP server through which it can be accessed publicly.

- The DHCP service of the Oracle allows the dynamic allocation of the Virtual IP addresses that allows the cluster to be joined together in a server.

- GNS provides automation to the system and removes the entire manual configuration with the dynamic nature of the system.

- Oracle Grid Infrastructure provides the support for Oracle Automatic Storage Management that has the solution for the database that is being used.

- Oracle Grid Infrastructure provides the solutions and software bundles to make it universal for its distribution.

- It provides a way to have the volume management, file system management and server pool management that is directly related to the Oracle RAC database.

- Oracle Grid Infrastructure provides complexity and can only be monitored and handled by the system administrator.

- Oracle Grid Infrastructure handles the grid functionality and provision to integrate the applications and services in the infrastructure.

- Load balancing advisory is a process through which the load of the applications and resources can be managed throughout the servers.

- It monitors the workload of the current activities from all the clusters and the instances that is being given on the server.

- The service that is being provided is active all the time to see the workload of the applications on the servers.

- To simplify it, it provides a percentage value to show the total workload of the instance and it flags the instance according to the quality.

- Load Balancing Advisory helps in maintaining the loads from the servers and equally distributes it among many other servers that are not currently working.

- Cluster Verification Utility is a tool in the Oracle Grid that is used to eliminate the errors that come up with the validations of the steps.

- It provides the verification on the changes that is being made in the configuration of the files or the system.

- The tool can be used with the command line interface and it is used to validate the configuration input as well such that during the installation it can be found out that everything is perfectly ok.

- The tool is used to verify the system pre-requisites that are related to Oracle Clusterware, ASM and the databases.

- There are few fix up scripts available if by any means the verification tool fails then these scripts can be used to automatically fix the errors.

- Oracle RAC provides High availability that becomes the foundation of the high end components used in Oracle’s Maximum Availability Architecture.

- Oracle RAC also provides Reliability for the Oracle Database that is being used in a widespread and allows user to easily remove the database server from a single point of failure.

- Oracle RAC focuses on Recoverability that if any failure occurs then the database should be such that it can recover from the failures. For example, connection failure.

- Oracle RAC provides an Error Detection mechanism that allows Oracle Clusterware to automatically monitors, detects and fix the error if any.

- Oracle RAC provides Scalability that is more useful in long term applications where the server runs out of the capacity and the cost is also low then it provides an easy way to increase the servers and pools to fit all the components.

- Oracle RAC uses a single system in the form of an image to configure and manage the servers in an easy way.

- It provides a database for the installed and configured applications from one location so that it can be managed in an easy way.

- The components required to be provided with it is as follows:

- Oracle Universal Installer (OUI) is used to manage the database that is related to the cluster and provide enterprise level configuration.

- Database configuration assistant (DBCA) that manages the database and its related functionality and services.

- Database upgrade assistant (DBUA) is the tool that allows the database to be upgraded when it is required on the server.

- Oracle Enterprise Manager provides a Grid Control that is used to deliver the centralized management system and provides configuration and administration capabilities.

- It provides the cost reduction plans and provides higher efficiency that allows the time to be saved for other server control actions.

- Oracle Enterprise Manager Database Control that is used as a graphical management tool to manage the database to make it configure automatically.

- It is related to the Oracle Clusterware and is used to manage the services of the Oracle RAC.

- It also manages the server pools that are being created with the Oracle Clusterware and provision to manage it from a single place.