RAC Consideration and Configurations

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Sept 24, 2015

RAC Source environment

To install and configure Dbvisit Replicate on RAC there are some special considerations:

  1. Dbvisit Replicate should be installed on all RAC nodes. Use shared storage to hold the configuration and PLOG directories so that this is accessible from all nodes to ensure that if Dbvisit Replicate is run from another node, it can continue where it left off. 
  2. Ensure Dbvisit Replicate is only ever active on ONE node in the RAC cluster. Dbvisit Replicate will mine ALL the redo threads from the one node.
  3. Ensure all redo threads are on shared storage and accessible from all nodes. This is to ensure that Dbvisit Replicate will be able to mine all redo and archivelog threads from one particular node. 
  4. Configure Dbvisit Replicate to use the TNS alias that will connect to the local instance only, but keep this alias same for all nodes. (e.g.: Use TNS alias myDB on node1 to connect to instance myDB1 and at the same time use TNS alias myDB on node2 to connect to instance myDB2.)  
  5. Use Oracle services to start Dbvisit Replicate on another node, if the node that currently runs Dbvisit Replicate fails. Dbvisit Replicate will ensure that the replication will restart from the same point where if failed. 

RAC target environment

To install and configure Dbvisit Replicate on RAC there are some special considerations:

  1. Dbvisit Replicate should be installed on all RAC nodes. Use shared storage to hold the configuration and PLOG directories so that this is accessible from all nodes to ensure that if Dbvisit Replicate is run from another node, it can continue where it left off. 
  2. Ensure Dbvisit Replicate is only ever active on ONE node in the RAC cluster. 
  3. Configure Dbvisit Replicate to use the TNS alias that will connect to the local instance only, but keep this alias same for all nodes. (e.g.: Use TNS alias myDB on node1 to connect to instance myDB1 and at the same time use TNS alias myDB on node2 to connect to instance myDB2.)  
  4. Use Oracle services to start Dbvisit Replicate on another node, if the node that currently runs Dbvisit Replicate fails. Dbvisit Replicate will ensure that the replication will restart from the same point where if failed. 

RAC configuration

For Oracle RAC, install the Dbvisit Replicate software on all RAC nodes in the cluster. Dbvisit Replicate will only ever be active on one node (however Dbvisit Replicate will mine all RAC threads simultaneously) and Oracle clusterware is used to start Dbvisit Replicate on another node should the current node go down. 

Please see http://www.dbvisit.com/content/freeTechGuides/RAC_and_HA_best_practices.pdf on how to configure Dbvisit Replicate with clusterware.