Recovery is the process of restoring the database to a fully functional state after one or more nodes in the system has experienced a software- or hardware-related failure. For example, a hardware failure can cause a node to lose database objects or to miss changes made to the database while offline. Vertica recovers nodes by querying replicas of the data stored on other nodes.
Recovery comes into play when you restart a node or the database. For more information, see Recovering the Database in the Vertica documentation.
Recovering Failed Nodes
When one node in a running database cluster fails, or if any files from the catalog or data directories are lost from any one of the nodes, you can recover the failed node using either the Administration Tools or the Management Console. For more information, see Failure Recovery in the Vertica documentation.
Recovering the Database After a Shutdown
If you lose the Vertica process on more than one node (for example, due to power loss), or if the servers are shut down without properly shutting down the database first, the database cluster indicates that it did not shut down gracefully the next time you start it. For more information, see Restarting the Database in the Vertica documentation.
Best Practices for Disaster Recovery
To protect your database from site failures caused by catastrophic disasters, maintain an off-site replica of your database. That way, if you do encounter a disaster, you can switch database users over to the standby database. How you choose to recover from a disaster depends on two factors:
For more information, see Best Practices for Disaster Recovery in the Vertica documentation.
There are several ways you can monitor database recovery:
- View the vertica.log files on each host. Each message is identified with a [Recover]string.
- Use the admintools view_cluster tool from the command line.
- Select View Database Cluster State from the admintools Main Menu.
- Query the PROJECTION_RECOVERIES and RECOVERY_STATUS system tables./li>
- View node status on the Management Console Overview page under the Database section.
To learn more about recovery in Vertica, see the Recovering the Database section in our core documentation.