You can manage a created replication group as needed in your actual Ops use cases. Specifically, you can set read-only instances as master instances, switch the roles of master and read-only instances, remove instances, or delete the replication group.
Prerequisites
You have created a global replication group and it is in Running status. For more information, see Creating Global Replication Group.
You have added an instance to the replication group and the instance is in Running status. For more information, see Creating Global Replication Group.
Setting a read-only instance as the master instance
You can set a read-only instance in a replication group as a master instance for data writes. This change only updates the instance configuration without causing data migration. The entire process takes approximately three minutes.
before the name of the target replication group to show its instance list.
2. Find the target read-only instance and click Set to Master in its Operation column.
Note:
You can set a ready-only instance as a master instance only if there are at least two read-only instance replicas in the replication group.
3. Read the prompt carefully in the Set to Master pop-up window and click OK.
In the instance list of the replication group, the instance status changes to switching instance role, and the instance role will change to master instance after the switch.
Setting the master instance as a read-only instance
You can also set a master instance added to a replication group to a read-only instance as detailed below.
Switching the instance role
You can switch the master instance only in the disaster recovery use case; that is, there is only one master instance and one read-only instance in the replication group. Usually, the replication group will become inaccessible for one minute during the switch.
Note:
When data is synced to the new master instance (the original read-only instance), it is still available for read access.
See the following steps for how to switch the master instance:
before the name of the target replication group to show its instance list.
2. Find the target read-only instance and click Switch with Master Instance in its Operation column.
3. Read the prompt carefully in the Switch with Master Instance pop-up window and click OK.
4. Both the master and read-only instances in the replication group enter the switching with master instance status. Wait for the switch to complete and then you can see that the original master instance is read-only, while the original read-only instance is now the master instance.
Removing an instance from a replication group
You can remove an instance from the replication group. The removed instance will stop syncing data from other instances in the replication group.
See the following steps for how to remove an instance from a replication group:
before the name of the target replication group to show its instance list.
2. Find the target instance and click Remove from Replication Group in its Operation column.
Note:
You cannot remove an instance if it is the only master instance in the replication group where read-only instances exist.
3. In the Remove from Replication Group pop-up window, confirm the instance information and click OK.
If the instance to be removed is a master instance, you need to select a removal mode.
Remove now: In this mode, the system disconnects data sync within the replication group immediately, without waiting for other nodes to complete data sync from this master instance. Some data may be lost.
Upon data sync completion: In this mode, the system sets the master instance as read-only, waits for other nodes in the replication group to complete data sync from it, disconnects the replication between it and all other nodes in the replication group, removes it from the replication group, cancels its read-only status, and then enables its write access.
4. In the instance list of the replication group, the instance status changes to Disassociating replication group. Wait for the removal to complete.
Deleting a replication group
You need to remove all instances in a replication group before you can delete it.
1. In the replication group list, select the target replication group and click Delete Replication Group in its Operation column.
2. In the Delete Replication Group pop-up window, confirm the replication group information and click OK.
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