Issue :
Error Message:
ORA-15064: communication failure with ASM instance
This error occurs when an Oracle Database instance loses communication with the Oracle Automatic Storage Management (ASM) instance. Since ASM manages the database storage, the database relies on continuous communication with the ASM instance to access disk groups.
When the connection between the database and ASM is interrupted, Oracle raises ORA-15064, and the database instance may terminate to prevent data inconsistency.
Cause of the Issue :
According to Oracle, ORA-15064 indicates that communication between the database instance and the ASM instance has been lost. This commonly occurs when the ASM instance is terminated, crashes, or becomes unreachable.
Common causes include:
- ASM instance crashed or was stopped.
- Oracle Clusterware (CRS) failure.
- ASM listener is unavailable.
- ASM disk groups are dismounted.
- Network interruption between RAC nodes.
- Shared storage failure.
- ASM shared memory (ORA-04031) issues.
- Oracle Cluster Synchronization Services (CSS) failure.
- Operating system or server reboot.
Often, ORA-15064 is accompanied by other errors such as ORA-03113, ORA-03135, ORA-04031, or CRS-related errors that identify the root cause.
Resolution :
Step 1 – Check the Database Alert Log
Review the database alert log.
tail -100 $ORACLE_BASE/diag/rdbms/<db_name>/<instance>/trace/alert_<instance>.log
Look for accompanying errors such as:
- ORA-03113
- ORA-03135
- ORA-04031
- ORA-00600
- CRS errors
Step 2 – Check ASM Instance Status
Verify whether the ASM instance is running.
ps -ef | grep asm_pmon
Or use:
srvctl status asm
If ASM is down, start it.
srvctl start asm
Step 3 – Verify Clusterware
Check Oracle Clusterware health.
crsctl check cluster
Display cluster resources.
crsctl stat res -t
If CRS is not running correctly, restart Clusterware after identifying the root cause.
Step 4 – Verify ASM Disk Groups
Connect to ASM.
SELECT name,
state,
type
FROM v$asm_diskgroup;
Ensure all required disk groups are in the MOUNTED state.
Step 5 – Review ASM Alert Log
Navigate to the ASM diagnostic directory.
cd $ORACLE_BASE/diag/asm/+asm/+ASM/trace
Review:
alert_+ASM.log
Look for:
- ORA-04031
- ORA-00600
- Disk failures
- Memory allocation errors
- Storage connectivity issues
Step 6 – Verify Storage Connectivity
Confirm that all ASM disks are visible.
Linux example:
oracleasm listdisks
If using ASMLib or multipath:
multipath -ll
Verify:
- SAN connectivity
- ASM devices
- Disk permissions
- Multipath configuration
Step 7 – Restart Database After ASM Recovery
After ASM is available:
srvctl start database -d <db_unique_name>
Or restart a specific instance:
srvctl start instance -d <db_unique_name> -i <instance_name>
Conclusion
ORA-15064 indicates that the database instance has lost communication with the Oracle ASM instance. The error itself is usually a symptom rather than the root cause. Administrators should examine the accompanying errors in the database and ASM alert logs, verify ASM and Clusterware status, confirm storage connectivity, and restore ASM availability before restarting the database. In most cases, resolving the underlying ASM, Clusterware, or storage issue also resolves ORA-15064.
