What is a VIP in RAC use for?
The VIP is an alternate Virtual IP address assigned to each node in a cluster. During a node failure the VIP of the failed node moves to the surviving node and relays to the application that the node has gone down. Without VIP, the application will wait for TCP timeout and then find out that the session is no longer live due to the failure.
How do we know which database instances are part of a RAC cluster?
You can query the V$ACTIVE_INSTANCES view to determine the member instances of the RAC cluster
What is a rolling upgrade?
A patch is considered a rolling if it is can be applied to the cluster binaries without having to shutting down the database in a RAC environment
What is cache fusion?
Ans:
Transferring of data between RAC instances by using private network. Cache Fusion is the remote memory mapping of Oracle buffers, shared between the caches of participating nodes in the cluster
What is the purpose of Private Interconnect?
Ans:
Clusterware uses the private interconnect for cluster synchronization (network heartbeat) and daemon communication between the clustered node
What is OCR file?
Ans:
RAC configuration information repository that manages information about the cluster node list and instance-to-node mapping information.
How do you identify the OCR file location?
Ans:
check /var/opt/oracle/ocr.loc or /etc/ocr.loc
# ocrcheck
What is Voting file/disk and how many files should be there?
Voting disk is akin to the quorum disk, which helps to avoid the split-brain syndrome. Oracle RAC uses the voting disk to manage cluster membership by way of a health check and arbitrates cluster ownership among the instances in case of network failures
Number of voting files must be odd i.e. 1, 3, 5, 7, 9
How do I identify the voting disk location?
Ans:
# crsctl query css votedisk
What is GNS?
Grid Naming service is alternative service to DNS , which will act as a sub domain in your DNS but managed by Oracle, with GNS the connection is routed to the cluster IP and manages internally
What is FAN?
Ans:
Applications can use Fast Application Notification (FAN) to enable rapid failure detection,
What is TAF and TAF policies?
Ans:
Transparent Application Failover (TAF) - A runtime failover for high availability environments, such as Real Application Clusters and Oracle Real Application Clusters Guard, TAF refers to the failover and re-establishment of application-to-service connections. It enables client applications to automatically reconnect to the database if the connection fails
How to know the public IPs, private IPs, VIPs in RAC?
Ans:
# olsnodes -n -p -i
Client Side Connect-Time Load Balance:
The client load balancing feature enables clients to randomize connection requests among the listeners.
This is done by client Tnsnames Parameter: LOAD_BALANCE.
The (load_balance=yes) instructs SQLNet
Server Side Listener Connection Load Balancing.
With server-side load balancing, the listener directs a connection request to the best instance currently providing the service.
Init parameter remote_listener should be set.
===================================================
The VIP is an alternate Virtual IP address assigned to each node in a cluster. During a node failure the VIP of the failed node moves to the surviving node and relays to the application that the node has gone down. Without VIP, the application will wait for TCP timeout and then find out that the session is no longer live due to the failure.
How do we know which database instances are part of a RAC cluster?
You can query the V$ACTIVE_INSTANCES view to determine the member instances of the RAC cluster
What is a rolling upgrade?
A patch is considered a rolling if it is can be applied to the cluster binaries without having to shutting down the database in a RAC environment
What is cache fusion?
Ans:
Transferring of data between RAC instances by using private network. Cache Fusion is the remote memory mapping of Oracle buffers, shared between the caches of participating nodes in the cluster
What is the purpose of Private Interconnect?
Ans:
Clusterware uses the private interconnect for cluster synchronization (network heartbeat) and daemon communication between the clustered node
What is OCR file?
Ans:
RAC configuration information repository that manages information about the cluster node list and instance-to-node mapping information.
How do you identify the OCR file location?
Ans:
check /var/opt/oracle/ocr.loc or /etc/ocr.loc
# ocrcheck
What is Voting file/disk and how many files should be there?
Voting disk is akin to the quorum disk, which helps to avoid the split-brain syndrome. Oracle RAC uses the voting disk to manage cluster membership by way of a health check and arbitrates cluster ownership among the instances in case of network failures
Number of voting files must be odd i.e. 1, 3, 5, 7, 9
How do I identify the voting disk location?
Ans:
# crsctl query css votedisk
What is GNS?
Grid Naming service is alternative service to DNS , which will act as a sub domain in your DNS but managed by Oracle, with GNS the connection is routed to the cluster IP and manages internally
What is FAN?
Ans:
Applications can use Fast Application Notification (FAN) to enable rapid failure detection,
What is TAF and TAF policies?
Ans:
Transparent Application Failover (TAF) - A runtime failover for high availability environments, such as Real Application Clusters and Oracle Real Application Clusters Guard, TAF refers to the failover and re-establishment of application-to-service connections. It enables client applications to automatically reconnect to the database if the connection fails
How to know the public IPs, private IPs, VIPs in RAC?
Ans:
# olsnodes -n -p -i
Client Side Connect-Time Load Balance:
The client load balancing feature enables clients to randomize connection requests among the listeners.
This is done by client Tnsnames Parameter: LOAD_BALANCE.
The (load_balance=yes) instructs SQLNet
Server Side Listener Connection Load Balancing.
With server-side load balancing, the listener directs a connection request to the best instance currently providing the service.
Init parameter remote_listener should be set.
===================================================
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