What DCS Instance Type Changes Are Supported?

Redis 3.0

From single-node to master/standby

The instance cannot be connected for several seconds and remains read-only for about one minute.

From master/standby to Proxy Cluster

1. If the data of a master/standby DCS Redis 3.0 instance is stored in multiple databases, or in non-DB0 databases, the instance cannot be changed to the Proxy Cluster type. A master/standby instance can be changed to the Proxy Cluster type only if its data is stored only on DB0.
2. The instance cannot be connected and remains read-only for 5 to 30 minutes.

Memcached

From single-node to master/standby

Services are interrupted for several seconds and remain read-only for about 1 minute.

Redis 4.0/5.0/6.0

From master/standby or read/write splitting to Proxy Cluster

1. After the instance is changed to Proxy Cluster, the multi-DB function is enabled for Proxy Cluster by default. In this case, you need to evaluate the impacts of the restrictions on using multi-DB and running commands. For details, see Notes and Procedure for Enabling Multi-DB for Proxy Cluster Instances, and Command Restrictions.
2. The used memory of the current instance must be less than 70% of the new instance's maximum memory. Otherwise, the change will be prohibited. To query the used memory of an instance, see parameter Used/Available Memory (MB) in Viewing and Modifying Basic Settings of a DCS Instance.
3. Some keys may be evicted if the current memory usage exceeds 90% of the total.
4. After the change is complete, you need to create alarm rules for the new instance by referring to Configuring DCS Monitoring and Alarms.
5. For a master/standby instance, ensure that its read-only IP address or read-only domain name is not directly referenced by your application.
6. If your application cannot reconnect to Redis or handle exceptions, you may need to restart the application after the change.
7. During the change, services are interrupted for seconds and remain read-only for about 1 minute. You are advised to perform the change during off-peak hours.

From Proxy Cluster to master/standby or read/write splitting

Redis 4.0/5.0/6.0

From master/standby to read/write splitting

1. Currently, only a master/standby instance with 4 GB or more memory can be changed to a read/write splitting instance with the same capacity.
2. Some keys may be evicted if the current memory usage exceeds 90% of the total.
3. After the change is complete, you need to create alarm rules for the new instance by referring to Configuring DCS Monitoring and Alarms.
4. Ensure that the read-only IP address or read-only domain name of the master/standby instance is not directly referenced by your application.
5. If your application cannot reconnect to Redis or handle exceptions, you may need to restart the application after the change.
6. During the change, services are interrupted for seconds. You are advised to perform the change during off-peak hours.
7. If an ACL account has been created for the master/standby instance, the instance cannot be changed to a read/write splitting one.
8. If SSL is enabled for a DCS Redis 6.0 instance, the instance cannot be changed to a read/write splitting one.