After a primary/secondary failover is triggered for your ApsaraDB MyBase for SQL Server instances, the system sends you a text message that includes the cause of the failover. This topic describes the reasons due to which a primary/secondary failover may be triggered for your ApsaraDB MyBase for SQL Server instances.

The following section describes the possible reasons:
  • Vulnerabilities

    Alibaba Cloud detects vulnerabilities in an ApsaraDB MyBase for SQL Server primary instance. The vulnerabilities may cause the instance to fail to run as expected. In this case, the system uses the ApsaraDB MyBase for SQL Server secondary instance to fix the vulnerabilities and performs a primary/secondary failover during a maintenance window. In most cases, if ApsaraDB MyBase for SQL Server detects a high-risk vulnerability, ApsaraDB MyBase for SQL Server fixes the high-risk vulnerability at the earliest opportunity and triggers a primary/secondary failover.

  • Manual operations

    You or an authorized Alibaba Cloud technical expert manually trigger a primary/secondary failover.

  • Instance failures

    Alibaba Cloud detects failures in an ApsaraDB MyBase for SQL Server primary instance. These failures cause the instance to fail to run as expected. In this case, the system initiates a primary/secondary failover to resume your business at the earliest opportunity. This helps mitigate the impact of the failures.

After a primary/secondary failover is complete, the corresponding instances enter the Running state. In this case, the instances can run as expected and you do not need to perform other operations. You can view the log records of primary/secondary failovers on the Service Availability page. For more information, see View primary/secondary switchover logs.