Oracle Clusterware
Oracle-provided clusterware that manages clusterdatabase processing including node membership, group services, global resourcemanagement, and high availability functions.
CRSD- OracleClusterware Daemon
The primary Oracle Clusterware process
crsd:Performs highavailability recovery and management operations such as maintaining the OCR andmanaging application resources. This process runs as the root user, or by auser in the admin group on Mac OSX-based systems. This process restarts automatically upon failure.
The CRSD process that creates the backupsalso creates and retains an OCR backup for each full
day and at the end of each week .
crsd :執行高可用性的恢復和管理操作:維護ocr，管理應用資源，該進程以root用戶身份運行。該進程在由於故障意外斷後會自動重啟。Crsd會在每天或者每周結束時對ocr進行備份。
The CRSD process maintains an internal counter to track how often a resourcehas been restarted.
Crsd進程維護內部的一個計數器來跟蹤特定資源的重啟次數：
- Engine for HAoperation
高可用性操作的引擎
- Manages 'application resources'
管理應用資源
- Starts, stops, and fails 'application resources' over to other nodes
啟動，停止，切換應用資源到其他節點
- Spawns separate 'actions' to start/stop/check application resources
產生獨立的操作來啟動、停止、檢查應用資源
- Maintains configuration profiles in the OCR (Oracle Configuration Repository)
維護ocr中的配置文件
- Stores current known state in the OCR.
把當前的狀態信息存儲在ocr中
- Runs as root
以root身份運行
- Is restarted automatically on failure
故障發生後能夠自動重啟
evmd: Event manager daemon. This process also starts the racgevt processto manage FAN server callouts.
Evmd：事件管理守護進程。這個進程也會啟動racgevt進程來管理 Fan進程的調用
- Generates events when things happen
當意外發生時產生事件
- Spawns a permanent child evmlogger
產生一個永久子進程--evmlogger
- Evmlogger, on demand, spawns children
Evmlogger會根據實際情況自動產生子進程
- Scans callout directory and invokes callouts.
- Runs as Oracle.
以oracle用戶身份運行
- Restarted automatically on failure
異常後能夠自動重啟
ocssd:Manages cluster node membership and runs as the oracle user; failureof this process results in cluster restart.
Ocssd：管理集群節點成員資格，以oracle用戶身份運行；該進程在異常時會自動重啟
- OCSSD isrequired with RAC databases and with non-RAC database when using ASM
使用 rac數據庫，或者單實例使用asm的數據庫都需要ocssd
- Provides access to node membership
提供對節點成員的訪問
- Provides group services
提供組服務
- Provides basic cluster locking
提供基本的集群鎖
- Integrates with existing vendor clusteware, when present
當有第3方集群軟件時能和他自動整合
- Can also runs without integration to vendor clustware
即使沒有第3方集群軟件，也能夠運行
- Runs as Oracle.
oracle用戶運行
- Failure exit causes machine reboot(RAC cluster only).
該進程異常會導致機器重啟
--- This is a feature to prevent data corruption in event of a split brain.
這個特性用來在發生腦裂時保護數據免收破壞。
oprocd : Process monitor for the cluster. Note that this process onlyappears on platforms that do not use vendor clusterware with OracleClusterware.
Oprocd：為集群提供進程監控。這個進程只有當沒有使用第3方集群時才會出現
The Oracle Clusterware Stack
Oracle Clusterwareconsists of two separate stacks: an upper stack anchored by the ClusterReady Services (CRS) daemon (crsd) and a lower stack anchored by the OracleHigh Availability Services daemon (ohasd). These two stacks have severalprocesses that facilitate cluster operations.
Oracle集群件由兩個獨立的堆棧組成：上層堆棧由crs固定，下層堆棧由oracle高可用服務固定ohasd。
. The following sections describe thesestacks in more detail:
■ The Cluster Ready Services Stack
■ The Oracle High Availability 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守護進程根據ocr中存儲的每個資源的配置信息來管理集群資源。相應的操作包括：start、stop、monitior、failover。當資源的狀態變化時crsd進程就會測試相應的事件。當安裝完RAC後， crsd 進程會監控oracle數據庫實例，監聽，以及當這些組件異常時就會自動重啟他們。
■ 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：通過控制集群成員資格和在節點加入或離開集群時通知集群成員來管理集群配置。如果使用第3方認證集群軟件，則css進程會和第3方集群件進行交互，來管理節點成員資格。
Cssdagent進程監控集群和提供io隔離。在oracle10g中cssdagen的工作由oprocd來完成。
Scan在公網必須能解析出最少一個ip地址，從高可用性和擴展性來考慮oracle建議配置一個可以解析出3個ip的scan。
在windows環境下對應的服務為：oraFenceService
如果cssdagent異常肯會導致oracle集群重啟節點。
■ Oracle ASM: Provides disk management for Oracle Clusterware and OracleDatabase.
■ Cluster Time Synchronization Service (CTSS): Provides timemanagement in a cluster for Oracle Clusterware.
Ctss：為oracle集群提供時間管理
■ Event Management (EVM): A background process that publishes eventsthat Oracle Clusterware creates.
Evm：用來發布oracle集群創建的events的後台進程。
■ Oracle Notification Service (ONS): A publish and subscribe servicefor communicating Fast Application Notification (FAN) events.
Ons:為通知fan events提供發布和訂閱的服務
■ 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：擴展集群以支持oracle特定的需求，和復雜資源。當FAN事件發生時該進程會運行服務器調用腳本。
■ 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 Services (ONS) components communicatewith other cluster component layers on other nodes in the same cluster databaseenvironment. These components are also the main communication links betweenOracle Database, applications, and the Oracle Clusterware high availabilitycomponents. In addition, these background processes monitor and manage databaseoperations.
Orarootagent：一個特別的oraagent，用來幫助crsd管理root用戶的資源：網絡，gridvip。
Css，evm，ons會和其他節點上的集群組件進行通信。這些組件也是oracle數據庫，應用，oracle高可用性組件間的主要通信鏈路。除此之外，這些後台進程也監控，管理數據庫的操作。
This section describes the processes thatcomprise the Oracle High Availability Services stack. The list includescomponents that are processes on Linux and UNIX operating systems, or services onWindows.
■ Cluster Logger Service (ologgerd): Receives information from allthe nodes in the cluster and persists in a CHM repository-based database. Thisservice runs on only two nodes in a cluster.
Ologgerd：從集群的所有節點接受信息並將信息存放到CHM信息庫中。該服務運行在集群中的所有節點。
■ System Monitor Service (osysmond): The monitoring and operatingsystem metric collection service that sends the data to the cluster loggerservice. This service runs on every node in a cluster.
Osysmond：監控和os度量收集，並將數據發送到集群日志服務。這個服務運行在集群中的每個節點。
■ Grid Plug and Play (GPNPD): Provides access to the Grid Plug andPlay profile, and coordinates updates to the profile among the nodes of thecluster to ensure that all of the nodes have the most recent profile.
Gpnpd：通過訪問gpnp配置文件，以及協調更新集群中所有節點的配置文件，確保所有節點擁有最近的配置文件。
■ Grid Interprocess Communication (GIPC): A support daemon thatenables Redundant Interconnect Usage.
Gipc：確保內聯冗余的使用的守護進程。
■ Multicast Domain Name Service (mDNS): Used by Grid Plug and Play tolocate profiles in the cluster, as well as by GNS to perform name resolution.The mDNS process is a background process on Linux and UNIX and on Windows.
Mdns：被gpnp用來定位集群中的配置文件；gns用他來作命名解析。
■ Oracle Grid Naming Service (GNS): Handles requests sent by externalDNS servers, performing name resolution for names defined by the cluster.
Gns：處理外部dns服務器的請求，為集群定義的名字進行命名解析
Table 1–1 lists the processes and servicesassociated with Oracle Clusterware components. In Table 1–1, if a UNIX or aLinux system process has an (r) beside it, then the process runs as the rootuser.
