The Cluster Ready Services Stack
The list in this section describes theprocesses that comprise CRS. The list includes components that are processes onLinux and UNIX operating systems, or services on Windows.
■ Cluster Ready Services (CRS): The primary program for managing highavailability operations in a cluster . The CRS daemon (crsd) manages clusterresources based on the configuration information that is stored in OCR for eachresource. This includes start, stop, monitor, and failover operations. The crsdprocess generates events when the status of a resource changes. When you haveOracle RAC installed, the crsd process monitors the Oracle database instance,listener, and so on, and automatically restarts these components when a failureoccurs.
Crs：集群中管理高可用性操作的主要程序。Crs守护进程根据ocr中存储的每个资源的配置信息来管理集群资源。相应的操作包括：start、stop、monitior、failover。当资源的状态变化时crsd进程就会测试相应的事件。当安装完RAC后， crsd 进程会监控oracle数据库实例，监听，以及当这些组件异常时就会自动重启他们。
■ Cluster Synchronization Services (CSS): Manages the clusterconfiguration by controlling which nodes are members of the cluster and by notifyingmembers when a node joins or leaves the cluster. If you are using certifiedthird-party clusterware, then CSS processes interface with your clusterware tomanage node membership information.Thecssdagent process monitors the cluster and provides I/O fencing. This serviceformerly was provided by Oracle Process Monitor Daemon (oprocd), also Note: TheSCAN must resolve to at least one address on the public network. For highavailability and scalability, Oracle recommends that you configure the SCAN toresolve to three addresses .See Also: Your platform-specific Oracle GridInfrastructure Installation
Guide installation documentation forinformation about system requirements and configuring network addresses Overviewof Oracle Clusterware Platform-Specific Software Components1-8 OracleClusterware Administration and Deployment Guide known as OraFenceService onWindows. A cssdagent failure may resultin Oracle Clusterware restarting the node.
Css：通过控制集群成员资格和在节点加入或离开集群时通知集群成员来管理集群配置。如果使用第3方认证集群软件，则css进程会和第3方集群件进行交互，来管理节点成员资格。
Cssdagent进程监控集群和提供io隔离。在oracle10g中cssdagen的工作由oprocd来完成。
Scan在公网必须能解析出最少一个ip地址，从高可用性和扩展性来考虑oracle建议配置一个可以解析出3个ip的scan。
在windows环境下对应的服务为：oraFenceService
如果cssdagent异常肯会导致oracle集群重启节点。
■ Oracle ASM: Provides disk management for Oracle Clusterware and OracleDatabase.
■ Cluster Time Synchronization Service (CTSS): Provides timemanagement in a cluster for Oracle Clusterware.
Ctss：为oracle集群提供时间管理
■ Event Management (EVM): A background process that publishes eventsthat Oracle Clusterware creates.
Evm：用来发布oracle集群创建的events的后台进程。
■ Oracle Notification Service (ONS): A publish and subscribe servicefor communicating Fast Application Notification (FAN) events.
Ons:为通知fan events提供发布和订阅的服务
■ Oracle Agent (oraagent): Extends clusterware to supportOracle-specific requirements and complex resources。 Thisprocess runs server callout scripts when FAN events occur. This process wasknown as RACG in Oracle Clusterware 11grelease 1 (11.1).
Oraagent：扩展集群以支持oracle特定的需求，和复杂资源。当FAN事件发生时该进程会运行服务器调用脚本。
■ Oracle Root Agent (orarootagent): A specialized oraagent processthat helps crsd manage resources owned by root, such as the network, and theGrid virtual IP address. The Cluster Synchronization Service (CSS), EventManagement (EVM), and Oracle Notification S