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    PolarDB:Add or Remove Nodes

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    PolarDB:Add or Remove Nodes

    Last Updated:Mar 03, 2026

    A PolarDB-X instance is a distributed cluster that consists of multiple nodes. PolarDB-X lets you scale an instance out or in by adding or removing nodes.

    Version limits

    • This feature is available only in the Enterprise Edition.

    • The required instance versions are as follows:

      • Version 2.4.0: polardb-2.4.0_5.4.19-20250923_xcluster5.4.20 or later.

      • Version 2.5.0: polardb-2.5.0_5.4.20-20251022_xcluster8.4.20-20250908 or later.

        Note

        • For more information about instance version rules, see Release notes.

        • Milvus Version. For more information, see View and Upgrade the Milvus Version.

        • If your Milvus Version is earlier than the required version, you can upgrade to the latest version to add or remove nodes. We recommend that you perform a comprehensive validation on an instance that runs the target version before you upgrade to prevent SQL compatibility issues.

    Procedure

    1. Log on to the PolarDB-X console.

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

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

    4. In the Actions column of the target instance, click Add Node or Remove Node.

    5. On the page that appears, specify the number of nodes to add or remove.

      Warning

      • Data migration occurs when you add or remove storage nodes. Perform this operation during your operations and maintenance (O&M) window. Long-running transactions that take more than 15 seconds to complete may be interrupted by metadata changes during the migration process.

      • Removing nodes reduces the maximum payload that your instance can handle. Before you confirm the operation, fully assess whether the remaining capacity can meet your business needs.

      • Historical backup sets become invalid after you remove storage nodes. You must back up your data immediately after the nodes are removed.

      • When you add or remove storage nodes, the system automatically triggers a data balancing task. This task consumes CPU and I/O resources on the storage nodes and may affect business performance. To prevent the data balancing task from running during peak hours, PolarDB-X provides a configurable O&M window. You can set this window to schedule data balancing tasks. For more information, see Configure the O&M window for scaling data balancing.

    6. Click Buy Now.

    7. In the dialog box that appears, click Sign and Place Order.

      After the operation is successful, the status of the instance in the console changes to Adding Nodes or Removing Nodes.

      Note

      Adding nodes is a paid operation. Removing nodes is free of charge.