When you perform operations such as configuration change, parameter modification, version upgrade, and primary-secondary switch on your TencentDB for MySQL instances, the instance switch will happen. During the instance switch, the instance will be unavailable temporarily. To minimize the impact on your businesses, TencentDB for MySQL provides switch within the maintenance window, allowing you to perform the switch in the instance maintenance period you set. The following impact statements need to be noted.
Note:
It is recommended that you perform operations involving instance switch at off-peak hours and ensure the application has an automatic reconnection mechanism.
Impact Description
When the instance architecture is two-node, three-node, or cluster edition, primary-secondary switch (for two/three-node architecture) or read-write node switch (for cluster edition architecture) may occur, causing service unavailability of no more than 30 seconds. Note:
When an instance is changed, the system automatically creates an instance on a host with enough resources and synchronizes the original instance data if local resources are insufficient. The synchronization process will not affect your use of the original instance. After synchronization, an instance switch will be performed, causing service unavailability of no more than 30 seconds.
When the instance architecture is single-node, service unavailability of a long time may occur. The specific duration is related to the data volume of the instance.
When an instance fails, the switch time may be extended.