Oracle10g RAC Service Architecture Overview of Real Application Cluster Ready Services, Nodeapps, and User Defined Services

Overview Service Architecture Cluster Ready Services (CRS) Nodeapps User defined Services ASM Services Internally Managed Services Monitoring Services

RAC Service Architecture Oracle 10g RAC features a service based architecture This is an improvement over 9i RAC in several ways Increased flexibility Increased flexibility Increased manageability Increased manageability Improvements in High Availability Improvements in High Availability Enables 10g Grid Deployment Enables 10g Grid Deployment

RAC Services and High Availability Oracle Services facilitate high availability of databases and related applications If key database resources become unavailable (network, storage, etc.): Instances and Services will be relocated to another node Instances and Services will be relocated to another node The “failed” node will be rebooted The “failed” node will be rebooted By default, after any server boot-up, Oracle attempts to restart all services on the node

Cluster Ready Services Manage the RAC Cluster Several Different Services OracleCRSService OracleCRSService Oracle CSService Oracle CSService OracleEVMService OracleEVMService OraFenceService OraFenceService Required for RAC installation Installed in its own CRS_HOME

CRS Basics Used to manage RAC Only one set of CRS Daemons per system Multiple instances share the same CRS Multiple instances share the same CRS CRS runs as both root and Oracle users CRS runs as both root and Oracle users CRS must be running before RAC can start

CRS Management Started automatically Can stop and start manually Start the OracleCRSService Start the OracleCRSService Stop the OracleCRSService Stop the OracleCRSService Uses the voting disk and OCR (Oracle Cluster Repository) Requires 3 network addresses Public Public Private Private Virtual Public Virtual Public

CRS Services OracleCRSService Cluster Ready Services Daemon Cluster Ready Services DaemonOracleCSService Oracle Cluster Synchronization Service Daemon Oracle Cluster Synchronization Service DaemonOracleEVMService Event Manager Daemon Event Manager DaemonOraFenceService Process Monitor Process Monitor

Cluster Ready Services Daemon OracleCRSService Runs as Administrator user Automatically restarted Manages Application Resources Starts, stops and fails-over application resources Maintains the OCR (Oracle Cluster Repository) Keeps state information in the OCR Keeps state information in the OCR

Oracle Cluster Synchronization Service Daemon OracleCSService Runs as Administrator user Maintains the heartbeat (failure causes system reboot) Provides Node Membership Node Membership Group Access Group Access Basic Cluster Locking Basic Cluster Locking Can integrate with 3 rd party clustering products or run standalone OracleCSService also works with non-RAC systems

Event Manager Daemon OracleEVMService Runs as Administrator user Restarts on failure Generates Events Starts the racgevt thread to invokes Server Callouts

Process Monitor OraFenceService Runs as Administrator user Locked in memory to monitor the cluster Provides I/O fencing OraFenceService periodically monitors cluster status, and can reboot the node if a problem is detected An OraFenceService failure results in Oracle Clusterware restarting the node

RACG RACG is a behind-the-scenes process (or thread) that extends clusterware to support Oracle-specific requirements and complex resources. Runs server callout scripts when FAN events occur. Runs as processes (or threads), not as a service (racgmain.exe, racgimon.exe)

Cluster Ready Services Management Log Files OracleCRSService OracleCRSService %ORA_CRS_HOME%\log\hostname\crsd %ORA_CRS_HOME%\log\hostname\crsd Oracle Cluster Registry (OCR) Oracle Cluster Registry (OCR) %ORA_CRS_HOME%log\hostname\ocr %ORA_CRS_HOME%log\hostname\ocr OracleEVMService OracleEVMService %ORA_CRS_HOME%\log\hostname\evmd %ORA_CRS_HOME%\log\hostname\evmd OracleCSService OracleCSService %ORA_CRS_HOME%log\hostname\cssd %ORA_CRS_HOME%log\hostname\cssd RACG RACG %ORA_CRS_HOME%log\hostname\racg %ORA_CRS_HOME%log\hostname\racg

Nodeapp Services Nodeapps are a standard set of Oracle application services that are automatically launched for RAC Virtual IP (VIP) Virtual IP (VIP) Oracle Net Listener Oracle Net Listener Global Services Daemon (GSD) Global Services Daemon (GSD) Oracle Notification Service (ONS) Oracle Notification Service (ONS) Nodeapp services run on each node Can be relocated to other nodes through the virtual IP Can be relocated to other nodes through the virtual IP

VIP (Virtual IP) Creates a virtual IP address used by the Listener The virtual IP address fails over between nodes Multiple virtual IP addresses can exist on the same system (during failover) Independent of the Oracle Instance Potential Problem if more than one database per node Potential Problem if more than one database per node

Global Services Daemon (GSD) The daemon which executes SRVCTL commands GSD receives requests from SRVCTL to execute administrative tasks, such as startup or shutdown The command is executed locally on each node, and the results are sent back to SRVCTL. The daemon is installed on the nodes by default. It is important that you do not kill this process and it should not be deleted.

Listener Server-side component of Oracle Net Listens for incoming client connection requests Manages the traffic to the server; when a client requests a network session with a server, the listener actually receives the request and brokers the client request If the client's information matches the listener's information, then the listener grants a connection to the server.

Oracle Notification Service (ONS) The Oracle Notification Service is installed automatically on each RAC node as a Node Application ONS starts automatically with each boot ONS uses a simple push/subscribe method to publish event messages to all RAC nodes with active ONS daemons

ONS and Fast Application Notification ONS can be configured to run on nodes hosting client or mid-tier applications ONS is the key component of Fast Application Notification (FAN) Can be utilized to extend RAC high availability and load balancing to mid-tier applications Can be utilized to extend RAC high availability and load balancing to mid-tier applications Independent of True Application Failover Independent of True Application Failover Less reliance on network configuration Less reliance on network configuration

User Defined Services User defined, named services may be created to manage database resources that are associated with application workloads One or more database instances may be mapped to a single service A database instance may be assigned to one or more services The Automated Workload Repository may be used to monitor Service metrics

User Defined Services and Failover Services can be defined with preferred and alternate instances A service may be assigned to start on preferred instances A service may be assigned to start on preferred instances The same service may have alternate instances assigned for failover The same service may have alternate instances assigned for failover If multiple services are assigned for the same database, the preferred and alternate instance assignments may be different for each service If multiple services are assigned for the same database, the preferred and alternate instance assignments may be different for each service

Automatic Storage Management Services Automatic Storage Management (ASM) is a storage option for creating and managing databases ASM operates like a Logical Volume Manager between the physical storage and the database. ASM operates like a Logical Volume Manager between the physical storage and the database. A small, automatically managed Oracle database instance is created on each node (if ASM is chosen as a storage option) A small, automatically managed Oracle database instance is created on each node (if ASM is chosen as a storage option) ASM instances start automatically as Oracle services ASM instances start automatically as Oracle services

Internally Managed Services When the Global Services Daemon is started as a part of the Node Applications, it in turn launches key internally managed services The Global Cache Service manages Cache Fusion and in- memory data buffers The Global Cache Service manages Cache Fusion and in- memory data buffers The Global Enqueue Service manages inter-instance locking and RAC recovery The Global Enqueue Service manages inter-instance locking and RAC recovery GCS and GES show up as OS processes or threads, but GSD is the only service that can be externally controlled GCS and GES together manage a set of “virtual” tables in memory, called the Global Resouce Directory

Global Cache Service (GCS) The controlling process that implements Cache Fusion. Manages the status and transfer of data blocks across the buffer caches of all instances. Tightly integrated with the buffer cache manager to enable fast lookup of resource information in the Global Resource Directory. Maintains the block mode for blocks in the global role. Employs various background processes (or threads) such as the Global Cache Service Processes (LMSn) and Global Enqueue Service Daemon (LMD).

Global Enqueue Service Monitor (LMON) Background process that monitors the entire cluster to manage global resources. Manages instance and process expirations and recovery for GCS. Handles the part of recovery associated with global resources

Global Resource Directory The data structures associated with global resources. It is distributed across all instances in a cluster. Global Cache Service and Global Enqueue Service maintain the Global Resource Directory to record information about resources and enqueues held globally. The Global Resource Directory resides in memory and is distributed throughout the cluster to all nodes. In this distributed architecture, each node participates in managing global resources and manages a portion of the Global Resource Directory.

Monitoring RAC Services %ORA_CRS_HOME%\bin\crs_stat NAME=ora.rac1.gsd NAME=ora.rac1.gsd TYPE=application TYPE=application TARGET=ONLINE TARGET=ONLINE STATE=ONLINE STATE=ONLINE NAME=ora.rac1.oem NAME=ora.rac1.oem TYPE=application TYPE=application TARGET=ONLINE TARGET=ONLINE STATE=ONLINE STATE=ONLINE NAME=ora.rac1.ons NAME=ora.rac1.ons TYPE=application TYPE=application TARGET=ONLINE TARGET=ONLINE STATE=ONLINE STATE=ONLINE

Monitoring RAC Services Creating a tabular report: %ORA_CRS_HOME%\bin\crs_stat -t NameType Target State Host ora.rac1.gsd application ONLINE ONLINE rac1 ora.rac1.oemapplication ONLINE ONLINE rac1 ora.rac1.ons application ONLINE ONLINE rac1 ora.rac1.vipapplication ONLINE ONLINErac1 ora.rac2.gsd application ONLINE ONLINE rac2 ora.rac2.oemapplication ONLINE ONLINE rac2 ora.rac2.ons application ONLINE ONLINE rac2 ora.rac2.vipapplication ONLINE ONLINErac2

Review What advantages does a service based architecture offer? What four services comprise Cluster Ready Services? Nodeapps consists of which four applications? True or False: a database instance may be assigned to multiple services

Summary Service Architecture Cluster Ready Services (CRS) OracleCRSService OracleCRSService OracleCSService OracleCSService OracleEVMService OracleEVMService OraFenceService OraFenceServiceNodeapps VIP VIP Listener Listener GSD GSD ONS ONS User defined Services ASM Services Internally managed services Global Cache Service Global Cache Service Global Enqueue Service Global Enqueue Service Global Resource Directory Global Resource Directory Monitoring Services