PolarDB:Manage data nodes

How it works

Storage resource pools organize data nodes into non-overlapping groups — each data node belongs to exactly one pool. PolarDB-X provides two built-in pools:

• `_default` — the default pool where all data nodes are placed unless assigned elsewhere

• `_recycle` — the recycle bin resource pool

You can associate databases, tables, and partitions with specific storage resource pools using the LOCALITY attribute, enabling workload and data isolation at the object level.

Because each data node can have its own resource allocation, you can tune individual nodes based on actual data distribution rather than applying a uniform configuration across the entire instance.

Common use cases:

• SaaS multi-tenant isolation — create a dedicated storage resource pool per tenant so that storage resources are fully isolated between tenants

• Workload-specific sizing — upgrade a heavily loaded data node without touching others

• Staged scale-in — release individual underutilized nodes to reduce costs

Prerequisites

Before you begin, make sure:

• Your PolarDB-X instance is version V5.4.18-17066805 or later to use the storage resource pool feature. After upgrading from an earlier version, existing data nodes are automatically assigned to the _default pool.

• Your instance is not a read-only instance. Data node management is unavailable for read-only instances.

Limitations after individual node reconfiguration

After you change the configuration of any single data node, the data nodes in your instance will have different configurations. When this happens:

• The overall instance configuration cannot be changed, but individual compute node and data node configurations can still be changed.

• To downgrade the instance, delete data nodes on the Data Node Management page instead of reducing the data node count through the instance configuration.

Create a custom storage resource pool

Create a custom storage resource pool to isolate storage resources for a specific tenant or workload.

1. Log on to the PolarDB-X console.

2. In the top navigation bar, select the region where your instance is deployed.

3. On the Instances page, click the PolarDB-X 2.0 tab.

4. Find the instance and click the instance name.

5. In the left-side navigation pane, click Data Node Management.

6. On the right side of the page, click Create Resource Pool.

7. In the Create Resource Pool dialog box, enter a name in the Resource Pool Name field. Optionally, expand Advanced Settings to select data nodes from the _recycle pool and associate them with the new pool. By default, no data nodes are selected. You can also add nodes after the pool is created.

8. Click OK.

Change the configuration of a data node

Upgrade or downgrade an individual data node based on its actual resource usage.

1. Log on to the PolarDB-X console.

2. In the top navigation bar, select the region where your instance is deployed.

3. On the Instances page, click the PolarDB-X 2.0 tab.

4. Find the instance and click the instance name.

5. In the left-side navigation pane, click Data Node Management.

6. In the Data Node List section, find the node and click Change Configurations in the Actions column.

   Note

   To change multiple data nodes at once, select the nodes and click Batch Configuration Change in the upper-right corner.

7. In the Data Node Configuration Change dialog box, select the new configuration and switching mode.

8. Click Pay to confirm.

Add a data node

Add data nodes to increase storage capacity.

1. Log on to the PolarDB-X console.

2. In the top navigation bar, select the region where your instance is deployed.

3. On the Instances page, click the PolarDB-X 2.0 tab.

4. Find the instance and click the instance name.

5. In the left-side navigation pane, click Data Node Management.

6. Click Add Node:

   • If your instance does not support storage resource pools, click Add Node in the upper-right corner.

   • If your instance supports storage resource pools, click Add Node on the tab of the target storage resource pool.

   Note

   If no custom storage resource pool exists, new nodes are added to the _default pool.

7. In the dialog box, select the number of nodes and click Buy Now.

Release a data node

1. Log on to the PolarDB-X console.

2. In the top navigation bar, select the region where your instance is deployed.

3. On the Instances page, click the PolarDB-X 2.0 tab.

4. Find the instance and click the instance name.

5. In the left-side navigation pane, click Data Node Management.

6. In the Data Node List section, find the node and click Release Node in the Actions column.

   Note

   • To release multiple nodes at once, select the nodes and click Delete Node in the upper-right corner.

   • Data nodes that serve as the default storage nodes for centralized tables cannot be released. The Release Node button is dimmed for these nodes. Their configuration can still be changed.