Instance states and impacts - Tair - Alibaba Cloud Documentation Center

This topic describes the different states of a Tair instance to help you manage your instances. When you restart or change the configurations of an instance, the state of the instance changes. This may cause issues. For example, a transient connection within seconds occurs on the instance.

Instance states

You can use one of the following methods to obtain the state of an instance:

Log on to the Tair console and view the state of an instance on the Instances page.
Call the DescribeInstances operation to query the state of an instance.

State in the console	State returned by the operation call	Action that triggers the state	Description
Creating	Creating	Create a Tair instance	After you create an instance, the instance enters the state. The instance cannot provide database services until the instance enters the Running state.
Running	Normal	None	The instance can provide database services in this state.
Converting	Transforming	Switch from pay-as-you-go to subscription	After you change the billing method of the instance to subscription, you cannot change the billing method back to pay-as-you-go. Before you change the billing method, we recommend that you evaluate your business requirements to make better use of the instance.
Changing Configuration	Changing	Change the configurations of an instance	For more information, see the "Change process and impacts" section of the Change the configurations of an instance topic.
Changing Configuration	Changing	Adjust the number of shards for an instance	The change to instance configurations may cause unstable latency. However, Tair supports scaling without leading to transient connections and the read-only state. We recommend that you perform this operation during off-peak hours and make sure that your application can automatically reconnect to the instance.
Restarting	Rebooting	Restart an instance	A transient connection occurs on the instance. We recommend that you perform this operation during off-peak hours and make sure that your application can automatically reconnect to the instance.
Upgrading Minor Version	MinorVersionUpgrading	Update the minor version of an instance	When you apply for resources, update the replica node, or synchronize data, your Tair service remains available. When you switch your workloads over from the original instance to a new instance or from the master node to the replica node in the original instance, you may experience transient connections that last for a few seconds. The original instance stays in the read-only state for up to 60 seconds until all data is synchronized. We recommend that you update the original instance during off-peak hours and make sure that your application is configured to automatically re-establish a connection.
Configuring Network	NetworkModifying	Change the VPC or vSwitch of a Tair instance	If you change the VPC or vSwitch of an instance, the instance encounters transient connections for 30 seconds. Make sure that you change the VPC or vSwitch during off-peak hours and your applications can automatically reconnect to the instance. If you change the VPC or vSwitch of an instance, the virtual IP address (VIP) of the instance is changed. If your applications are connected to the VIP of the instance, the connections are closed after the VIP is changed. Note After you change the VPC or vSwitch of an instance, the endpoint of the instance, such as `r-hp3bpn39cs1vu****.redis.hangzhou.rds.aliyuncs.com`, remains unchanged. We recommend that you connect your applications to instances by using endpoints. A VIP change interrupts Data Management (DMS) for a short period of time. For more information about DMS, see Overview. After the VIP is changed, the connections are resumed. After you change the VPC or vSwitch of an instance, clear the cache on clients. Otherwise, clients may be unable to write data to the instance and can only read data from the instance.
		Change the endpoint or port of an instance	Clients can no longer connect to the Tair instance by using the original endpoints. Update the connection information on the clients at the earliest opportunity.
		Apply for a public endpoint for a Tair instance	None
		Release a public endpoint for a Tair instance	Clients can no longer connect to the Tair instance by using the original public endpoint. Update the connection information on the clients at the earliest opportunity.
		Enable the direct connection mode	If you enable the direct connection mode, you cannot perform the following operations: Change the configurations of an instance Migrate an instance across zones You must release the private endpoint before you can perform the preceding operations.
		Release a private endpoint for a Tair instance	Clients can no longer connect to the instance by using the original private endpoint. Update the connection information on the clients at the earliest opportunity.
Configuring SSL	SSLModifying	Configure SSL encryption	The instance restarts after you enable SSL encryption or update the certificate validity period. A transient connection occurs on the instance. We recommend that you perform this operation during off-peak hours and make sure that your application can automatically reconnect to the instance.
Migrating to Another Zone	ZoneMigrating	Migrate an instance across zones	A transient connection occurs on the instance. We recommend that you perform this operation during off-peak hours and make sure that your application can automatically reconnect to the instance. If you migrate an instance across zones, the VIP of the instance such as 172.16.88.60 is changed. However, the endpoint of the instance remains unchanged. We recommend that you connect to the instance by using the endpoint. If you use a VIP to connect to the instance, the connection fails. If the minor version of the instance is outdated, the system updates it to the latest version to ensure high performance and stability.
Flushing Instance	Flushing	Delete data	If you choose to delete all data, take note of the following impacts: The instance runs the FLUSHALL command to delete all data from the instance. The deleted data cannot be restored. This operation immediately deletes all data from the instance and can affect your online services. Proceed with caution. We recommend that you perform this operation during off-peak hours.
Deleting Expired Data	CleaningUpExpiredData	Delete data	If you choose to delete expired data, take note of the following impacts: The instance runs the SCAN command to delete all the expired data from the instance. The deleted data cannot be restored. This operation immediately deletes all the expired data from the instance and can affect your online services. Proceed with caution. We recommend that you perform this operation during off-peak hours.
Switching	HASwitching	Manually switch workloads from a master node to a replica node	The data nodes on which the switchover is performed are disconnected for a few seconds. A switchover has potential data loss risks. For example, the data may become inconsistent between the master and replica nodes due to synchronization latency. To prevent potential data loss risks caused by the switchover and data doublewrite caused by the Domain Name System (DNS) cache, the data nodes become read-only for up to 30 seconds. After an instance enters the Switching state, you cannot manage this instance. For example, you cannot modify the instance configurations or migrate the instance to another zone.
Disabled	Inactive	None	The instance expires and cannot provide database services. If you want to continue using the instance, you must manually renew the instance. For more information, see Renewal policy.
Released	None	Manually or automatically release an instance that is overdue or expired	The instance is released and cannot provide database services. The instance is not displayed on the Instances page. If you want to continue using the instance, you can find and restore the instance from the recycle bin. For more information, see Manage instances in the recycle bin.