Scale Your TiDB Cluster

Note

You cannot scale a Serverless Tier cluster.
When a cluster is in the MODIFYING status, you cannot perform any new scaling operations on it.

You can scale a TiDB cluster in the following dimensions:

Node number of TiDB, TiKV, and TiFlash
Node storage of TiKV and TiFlash
Node size (including vCPUs and memory) of TiDB, TiKV, and TiFlash

For information about how to determine the size of your TiDB cluster, see Determine Your TiDB Size.

Note

If the node size of TiDB or TiKV is set as 2 vCPU, 8 GiB (Beta) or 4 vCPU, 16 GiB, note the following restrictions. To bypass these restrictions, you can increase your node size first.

The node quantity of TiDB can only be set to 1 or 2, and the node quantity of TiKV is fixed to 3.
2 vCPU TiDB can only be used with 2 vCPU TiKV, and 2 vCPU TiKV can only be used with 2 vCPU TiDB.
4 vCPU TiDB can only be used with 4 vCPU TiKV, and 4 vCPU TiKV can only be used with 4 vCPU TiDB.
TiFlash is unavailable.

Change node number

You can change the number of TiDB, TiKV, or TiFlash nodes.

Increase node number

To increase the number of TiDB, TiKV, or TiFlash nodes, take the following steps:

In the TiDB Cloud console, navigate to the Clusters page of your project.
In the row of the cluster that you want to scale, click ....
Tip
Alternatively, you can also click the name of the cluster that you want to scale on the Clusters page and click ... in the upper-right corner.
Click Modify in the drop-down menu. The Modify Cluster page is displayed.
On the Modify Cluster page, increase the number of TiDB, TiKV, or TiFlash nodes.
Click Confirm.

You can also increase the number of TiDB, TiKV, or TiFlash nodes using TiDB Cloud API through the Modify a Dedicated Tier cluster endpoint. Currently, TiDB Cloud API is still in beta. For more information, see TiDB Cloud API Documentation.

Decrease node number

To decrease the number of TiDB nodes, take the following steps:

In the TiDB Cloud console, navigate to the Clusters page of your project.
In the row of the cluster that you want to scale, click ....
Tip
Alternatively, you can also click the name of the cluster that you want to scale on the Clusters page and click ... in the upper-right corner.
Click Modify in the drop-down menu. The Modify Cluster page is displayed.
On the Modify Cluster page, decrease the number of TiDB nodes.
Click Confirm.

To decrease the number of TiKV or TiFlash nodes, you need to submit a support ticket. The PingCAP support team will contact you and complete the scaling within the agreed time.

Warning

Decreasing TiKV or TiFlash node number can be risky, which might lead to insufficient storage space, excessive CPU usage, or excessive memory usage on remaining nodes.

To submit a support ticket, perform the steps in TiDB Cloud Support. For each node to be scaled, provide the following information in the Description box:

Cluster name: xxx
Cloud provider: GCP or AWS
Node type: TiKV or TiFlash
Current node number: xxx
Expected node number: xxx

Change node storage

You can change the node storage of TiKV or TiFlash.

Increase node storage

Note

AWS has a cooldown period of node storage changes. If your TiDB cluster is hosted on AWS, after changing the node storage or node size of TiKV or TiFlash, you must wait at least six hours before you can change it again.

To increase the node storage of TiKV or TiFlash, take the following steps:

In the TiDB Cloud console, navigate to the Clusters page of your project.
In the row of the cluster that you want to scale, click ....
Tip
Alternatively, you can also click the name of the cluster that you want to scale on the Clusters page and click ... in the upper-right corner.
Click Modify in the drop-down menu. The Modify Cluster page is displayed.
On the Modify Cluster page, increase the node storage of TiKV or TiFlash.
Click Confirm.

You can also increase the storage of a TiKV or TiFlash node using TiDB Cloud API through the Modify a Dedicated Tier cluster endpoint. Currently, TiDB Cloud API is still in beta. For more information, see TiDB Cloud API Documentation.

Decrease node storage

For a running cluster, AWS and Google Cloud do not allow in-place storage capacity downgrade.

Increase node size

Note

Increasing node size is only available to clusters that are hosted on AWS and created after 2022/12/31.
AWS has a cooldown period of node size changes. If your TiDB cluster is hosted on AWS, after changing the node storage or node size of TiKV or TiFlash, you must wait at least six hours before you can change it again.

You can increase the node size for TiDB, TiKV, and TiFlash. Decreasing the node size is not supported.

To increase the node size, take the following steps:

In the TiDB Cloud console, navigate to the Clusters page for your project.
In the row of the cluster that you want to scale, click ....
Click Modify in the drop-down menu. The Modify Cluster page is displayed.
On the Modify Cluster page, increase the node size as you need.
Click Confirm.