Backup fails when the database status is displayed as "."

Description

If you have changed the RAC database instance status using SQL *Plus instead of srvctl, the status of the instance is displayed as ".". When you try to create a backup of that instance, the operation fails.

Error message

PL-SCO-20046: Validate prefer host operation for SnapCenter Plug-in for Oracle Database failed for database database_name on host host_name with error ORACLE-00300: Error executing srvctl command srvctl status database -d database_name -v. The command returned: [Instance database_name1 is running on node host_name-node1. Instance status: ., Instance database_name2 is running on node host_name-node2. Instance status: Dismounted.]) ERROR SnapManagerWeb_361 PID=[8872] TID=[145] ErrorCode (-1), ErrorMessage (Resource database_name will be skipped for the current operation, as the preferred hosts are exhausted or in maintenance mode for this resource. See if more preferred hosts can be configured.)

You should always change the database status using srvctl.