Oracleclusterware10g/11g process details

The oracle 10g clusterware processes on UNIX-based systems are:

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: perform high-availability recovery and management operations: maintain ocr and manage application resources. The process runs as a root user. This process will be automatically restarted after an unexpected fault occurs. Crsd backs up ocr every day or every week.

The CRSD process maintains an internal counter to track how often a resourcehas been restarted.

The Crsd Process maintains an internal counter to track the number of reboots of a specific resource:

-Engine for HAoperation

High-availability Engine
-Manages 'application resources'

Manage application resources
-Starts, stops, and fails 'application resources' over to other nodes

Start, stop, and switch application resources to other nodes
-Spawns separate 'actions' to start/stop/check application resources

Create independent operations to start, stop, and check application resources
-Maintains configuration profiles in the OCR (Oracle Configuration Repository)

Maintain the configuration file in ocr
-Stores current known state in the OCR.

Store the current status information in ocr
-Runs as root

Run as root
-Is restarted automatically on failure
Automatically restarts after a fault occurs.

Evmd:Event manager daemon. This process also starts the racgevt processto manage FAN server callouts.

Evmd: The Event Management daemon. This process also starts the racgevt process to manage the Fan process calls.
-Generates events when things happen

An event occurs when an accident occurs.
-Spawns a permanent child evmlogger

Generate a permanent sub-process-evmlogger
-Evmlogger, on demand, spawns children

Evmlogger automatically generates sub-processes based on actual conditions.
-Scans callout directory and invokes callouts.

-Runs as Oracle.

Run as an oracle user
-Restarted automatically on failure

Automatic Restart upon exception

Ocssd:Manages cluster node membership and runs as the oracle user; failureof this process results in cluster restart.

Ocssd: Manages cluster node membership and runs as an oracle user. The process restarts automatically when an exception occurs.

-OCSSD isrequired with RAC databases and with non-RAC database when using ASM

Ocssd is required for databases that use rac databases or databases that use asm for a single instance.

-Provides access to node membership

Provide access to node members
-Provides group services

Provide Group Services
-Provides basic cluster locking

Provides basic cluster locks
-Integrates with existing vendor clusteware, when present

Automatically integrated with 3rd-party cluster Software
-Can also runs without integration to vendor clustware

Even if there is no 3rd-party cluster software, it can run
-Runs as Oracle.

Oracle user running
-Failure exit causes machine reboot (RAC cluster only).

This process is abnormal and causes the machine to restart.
--- This is a feature to prevent data upload uption in event of a split brain.

This feature is used to protect data from damage when split-brain occurs.

Oprocd:Process monitor for the cluster. Note that this process onlyappears on platforms that do not use vendor clusterware with OracleClusterware.

Oprocd: Provides Process Monitoring for clusters. This process appears only when the cluster of the third party is not used.

Oracle 11g clusterwareprocesses on UNIX-based systems are:

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.

An Oracle cluster consists of two independent stacks: the upper stack is fixed by crs, and the lower stack is fixed by the oracle High Availability Service (ohasd.

. The following sections describe thesestacks in more detail:

■ The Cluster Ready Services Stack

■ The Oracle High Availability Services Stack

The Cluster Ready Services Stack

The list in this section describes theprocesses that comprise CRS. The list nodes 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 des 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: the main program for managing high-availability operations in a cluster. The Crs daemon manages cluster resources based on the configuration information of each resource stored in ocr. The corresponding operations include start, stop, monitior, and failover. When the resource status changes, the crsd process will test the corresponding event. After RAC is installed, the crsd process monitors and listens to oracle database instances and automatically restarts these components when they are abnormal.

■ Cluster Synchronization Services (CSS): Manages the clusterconfiguration by controlling which nodes are members of the cluster and by notifyingmembers when a node joins or Lethe leaves 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 handling 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: Manages cluster configurations by controlling cluster membership and notifying cluster members when nodes join or leave the cluster. If the cluster software is verified by the third party, the css process interacts with the cluster component of the third party to manage the node membership.

Cssdagent Process Monitoring cluster and io isolation. In oracle10g, the job of cssdagen is completed by oprocd.

Scan must be able to parse at least one ip address on the public network. In terms of high availability and scalability, we recommend that you configure a scan that can parse three ip addresses in oracle.

In windows, the corresponding service is oraFenceService.

If the cssdagent is abnormal, the oracle cluster restarts the node.

■ Oracle ASM: Provides disk management for Oracle Clusterware and OracleDatabase.

■ Cluster Time Synchronization Service (CTSS): Provides timemanagement in a cluster for Oracle Clusterware.

Ctss: provides time management for oracle Clusters

■ Event Management (EVM): A background process that publishes eventsthat Oracle Clusterware creates.

Evm: the background process used to publish the events created by the oracle cluster.

■ Oracle Notification Service (ONS): A publish and subscribe servicefor communicating Fast Application Notification (FAN) events.

Ons: provides publishing and subscription services for notifying fan events

■ Oracle Agent (oraagent): Extends clusterware to supportOracle-specific requirements and complex resources. Thisprocess runs server callout scripts when FAN events occur. This process is known as RACG in Oracle Clusterware 11 grelease 1 (11.1 ).

Oraagent: expands the cluster to support specific oracle requirements and complex resources. When a FAN event occurs, the process runs the server call script.

■ 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: A special oraagent used to help crsd manage root user resources: Network and gridvip.

Css, evm, and ons communicate with cluster components on other nodes. These components are also the main communication link between oracle databases, applications, and oracle High Availability components. In addition, these background processes also monitor and manage database operations.

The Oracle High Availability Services Stack

This section describes the processes thatcomprise the Oracle High Availability Services stack. The list items descomponents that are processes on Linux and UNIX operating systems, or services on Windows.

■ Cluster Logger Service (ologadh): Attributes es information from allthe nodes in the cluster and persists in a CHM repository-based database. Thisservice runs on only two nodes in a cluster.

Ologadh: receives information from all nodes in the cluster and stores the information in the CHM database. This service runs on all nodes in the cluster.

■ 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: Collects monitoring and OS metrics and sends data to the cluster Log service. This service runs on every node in the cluster.

■ 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: access the gpnp configuration file and coordinate the configuration files of all nodes in the cluster to ensure that all nodes have the most recent configuration files.

■ Grid Interprocess Communication (GIPC): A support daemon thatenables Redundant Interconnect Usage.

Gipc: the daemon process used to ensure inline redundancy.

■ 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: used by gpnp to locate the configuration file in the cluster. gns uses it for name resolution.

■ Oracle Grid Naming Service (GNS): Handles requests sent by externalDNS servers, please Ming name resolution for names defined by the cluster.

Gns: Processes requests from external dns servers and performs name resolution for cluster-defined names

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.