You can run the ENABLE CLUSTER SYNCHRONIZATION command on a standby cluster to enable data synchronization, so as to connect to the primary cluster. However, errors may occur during the execution of the command. This topic describes possible errors that may occur after you execute the ENABLE CLUSTER SYNCHRONIZATIONcommand, and their causes and solutions.
Error 1: standby cluster not exist
Possible cause
The CLUSTER_ID of the standby cluster specified in the command does not exist.
Handling method
Run the following command on the primary cluster to query the V$OB_STANDBY_STATUS view and check the value of CLUSTER_ID of the standby cluster:
obclient> SQL> SELECT CLUSTER_ID, CLUSTER_ROLE, CLUSTER_STATUS FROM V$OB_STANDBY_STATUS;
+-------------+----------------------+--------------------+
| CLUSTER_ID | CLUSTER_ROLE | CLUSTER_STATUS |
+-------------+----------------------+--------------------+
| 1 | PHYSICAL STANDBY | DISABLED |
+-------------+----------------------+--------------------+
Error 2: enable read only cluster not allowed
Possible cause
Data synchronization cannot be enabled for read-only clusters.
Handling method
None
Error 3: enable primary cluster not allowed
Possible cause
Data synchronization cannot be enabled for the primary cluster.
Handling method
Run the following command on the primary cluster to query the
V$OB_STANDBY_STATUSview and check the information about all standby clusters:obclient> SELECT CLUSTER_ID, CLUSTER_ROLE, CLUSTER_STATUS FROM V$OB_STANDBY_STATUS; +-------------+-----------------------+--------------------+ | CLUSTER_ID | CLUSTER_ROLE | CLUSTER_STATUS | +-------------+-----------------------+--------------------+ | 1 | PHYSICAL STANDBY | DISABLED | +-------------+-----------------------+--------------------+Enable data synchronization the standby cluster.
Error 4: standby cluster failover epoch is larger than primary cluster, enable cluster not allowed
Possible cause
The standby cluster has redundant failover information. This indicates that data in the standby cluster is inconsistent with that in the primary and standby clusters. Therefore, data synchronization cannot be enabled.
Possible methods
Run the following command on the primary cluster and the standby cluster to query the V$OB_CLUSTER_FAILOVER_INFO view for the failover positions, and contact technical support.
obclient> SELECT `FAILOVER#`, TENANT_ID, SYS_TABLE_SCN, USER_TABLE_SCN FROM V$OB_CLUSTER_FAILOVER_INFO;
Error 5: standby cluster has more schema_version of sys than primary, enable cluster not allowed
Possible cause
The system tenant of the standby cluster has more Schema versions than the primary cluster. Therefore, data synchronization cannot be enabled.
Handling method
Contact technical support.
Error 6: standby cluster has more freeze_info than primary, enable cluster not allowed
Possible cause
The standby cluster has more freeze information than the primary cluster. Therefore, data synchronization cannot be enabled.
Handling method
Run the following command on the primary cluster and the standby cluster to query the freeze information, and contact technical support.
obclient> SELECT * FROM __ALL_VIRTUAL_FREEZE_INFO;