Verifying That Instances are Running

To verify that a database instance is available, use Oracle Enterprise Manager, SRVCTL, or SQL*Plus.

Using SRVCTL to Verify That Instances are Running

You can use SRVCTL to verify that instances are running on a particular database.

The following command provides an example of using SRVCTL to check the status of the database instances for the Oracle RAC database named mail:

$ srvctl status database -db mail

This command returns output similar to the following:

Instance mail1 is running on node node11
Instance mail2 is running on node node10

Additionally, you can check whether a PDB is running in the cluster, as follows:

$ srvctl status pdb -db db_unique_name -pdb pdb_name

You can use SQL*Plus to verify that database instances are running.

On any node, from a SQL*Plus prompt, connect to a database instance by using a Net Services connection string, typically an instance-specific alias from your tnsnames.ora file.
```
CONNECT /@db1 as SYSRAC
```

Query the V$ACTIVE_INSTANCES view, using the following statement:

CONNECT SYS/as SYSRAC
Enter password: password
SELECT * FROM V$ACTIVE_INSTANCES;

This query returns output similar to the following:

INST_NUMBER INST_NAME    
-----------  ----------------- 
1            db1-sun:db1  
2            db2-sun:db2  
3            db3-sun:db3

The output columns for this example are shown in the following table.

Table: Descriptions of V$ACTIVE_INSTANCES Columns

Column	Description
`INST_NUMBER`	Identifies the instance number.
`INST_NAME`	Identifies the host name and instance name as `host_name`: `instance_name`.