CLUSTERWARE Y LA MADRE QUE LE PARIO

CLUSTERWARE Y LA MADRE QUE LE PARIO

aqui voy a comentar todo ese follon de siglas que no hay chacho que se aclare

In fact, CRS is much more than the cluster software. It provides a method to configure High Availability (HA) services and Oracle Notification Services (ONS). We will examine more details on the CRS in later part of this chapter.

ONS proporciona servicio de mensajeria proveyendo a listeners y AS el estado-disponibilidad de cada nodo del cluster. ONS es la base para otros servicios como FAN y FCF

... y si no te ha quedado claro:

The following list describes some of the major Oracle Clusterware background processes. The list includes components that are processes on Linux and UNIX operating systems, or services on Windows.

• Cluster Ready Services (CRS)—The primary program for managing high availability operations in a cluster. Anything that the CRS process manages is known as a cluster resource, which could be a database, an instance, a service, a listener, a virtual IP (VIP) address, an application process, and so on. The CRS process manages cluster resources based on the resource's configuration information that is stored in the OCR. This includes start, stop, monitor and failover operations. The CRS process generates events when a resource status changes. When you have installed Oracle RAC, the CRS process monitors the Oracle database instance, listener, and so on, and automatically restarts these components when a failure occurs. By default, the CRS process makes three attempts to start the Oracle Notification Service (ONS), one attempt to start an Oracle database, and five attempts to restart other database components. The CRS process does not attempt to restart the VIP. After these initial attempts, the CRS process does not make further restart attempts if the resource does not restart.

• Cluster Synchronization Services (CSS)—Manages the cluster configuration by controlling which nodes are members of the cluster and by notifying members when a node joins or leaves the cluster. If you are using certified third-party clusterware, then the css process interfaces with your clusterware to manage node membership information.

• Event Management (EVM)—A background process that publishes events that Oracle Clusterware creates.

• Oracle Notification Service (ONS)—A publish and subscribe service for communicating Fast Application Notification (FAN) events.

• Oracle Process Monitor Daemon (OPROCD)—This process (the OraFenceService service in Windows) is locked in memory to monitor the cluster and provide I/O fencing. The OPROCD periodically wakes up and checks that the interval since it last awoke is within the expected time. If not, then OPROCD resets the processor and restarts the node. An OPROCD failure results in Oracle Clusterware restarting the node.

• RACG—Extends clusterware to support Oracle-specific requirements and complex resources. Runs server callout scripts when FAN events occur.