Determine Your TiDB Size

This document describes how to determine the size of a Dedicated Tier cluster.

Size TiDB

TiDB is for computing only and does not store data. It is horizontally scalable.

You can configure both node size and node quantity for TiDB.

To learn performance test results of different cluster scales, see TiDB Cloud Performance Reference.

TiDB node size

The supported node sizes include the following:

• 2 vCPU, 8 GiB (Beta)
• 4 vCPU, 16 GiB
• 8 vCPU, 16 GiB
• 16 vCPU, 32 GiB

TiDB node quantity

For high availability, it is recommended that you configure at least two TiDB nodes for each TiDB Cloud cluster.

Size TiKV

TiKV is responsible for storing data. It is horizontally scalable.

You can configure node size, node quantity, and node storage for TiKV.

To learn performance test results of different cluster scales, see TiDB Cloud Performance Reference.

TiKV node size

The supported node sizes include the following:

• 2 vCPU, 8 GiB (Beta)
• 4 vCPU, 16 GiB
• 8 vCPU, 32 GiB
• 8 vCPU, 64 GiB
• 16 vCPU, 64 GiB

TiKV node quantity

The number of TiKV nodes should be at least 1 set (3 nodes in 3 different Available Zones).

TiDB Cloud deploys TiKV nodes evenly to all availability zones (at least 3) in the region you select to achieve durability and high availability. In a typical 3-replica setup, your data is distributed evenly among the TiKV nodes across all availability zones and is persisted to the disk of each TiKV node.

Recommended number of TiKV nodes: ceil(compressed size of your data ÷ TiKV storage usage ratio ÷ one TiKV capacity) × the number of replicas

Supposing the size of your MySQL dump files is 5 TB and the TiDB compression ratio is 40%, the storage needed is 2048 GiB.

Generally, the usage ratio of TiKV storage is not recommended to exceed 80%.

For example, if you configure the node storage of each TiKV node on AWS as 1024 GiB, the required number of TiKV nodes is as follows:

Minimum number of TiKV nodes: ceil(2048 ÷ 0.8 ÷ 1024) × 3 = 9

TiKV node storage

The supported node storage of different TiKV node sizes is as follows:

Size TiFlash

TiFlash synchronizes data from TiKV in real time and supports real-time analytics workloads right out of the box. It is horizontally scalable.

You can configure node size, node quantity, and node storage for TiFlash.

TiFlash node size

The supported node sizes include the following:

• 8 vCPU, 64 GiB
• 16 vCPU, 128 GiB

Note that TiFlash is unavailable when the vCPU size of TiDB or TiKV is set as 2 vCPU, 8 GiB (Beta) or 4 vCPU, 16 GiB.

TiFlash node quantity

TiDB Cloud deploys TiFlash nodes evenly to different availability zones in a region. It is recommended that you configure at least two TiFlash nodes in each TiDB Cloud cluster and create at least two replicas of the data for high availability in your production environment.

The minimum number of TiFlash nodes depends on the TiFlash replica counts for specific tables:

Minimum number of TiFlash nodes: min((compressed size of table A * replicas for table A + compressed size of table B * replicas for table B) / size of each TiFlash capacity, max(replicas for table A, replicas for table B))

For example, if you configure the node storage of each TiFlash node on AWS as 1024 GiB, and set 2 replicas for table A (the compressed size is 800 GiB) and 1 replica for table B (the compressed size is 100 GiB), then the required number of TiFlash nodes is as follows:

Minimum number of TiFlash nodes: min((800 GiB * 2 + 100 GiB * 1) / 1024 GiB, max(2, 1)) ≈ 2

TiFlash node storage

The supported node storage of different TiFlash node sizes is as follows: