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Scale MySQL sync cluster
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Scale MySQL sync cluster

The MySQL sync cloud database cluster can be scaled. For example:

  • increase vCPU and RAM to improve cluster performance;
  • change the configuration lineup with local disk to another lineup with local disk — the disk size must necessarily be larger than in the previous configuration, the number of vCPUs and RAM can be reduced or increased.Change the lineup with local disk to the lineup with network disk and vice versa is possible only during cluster recovery.

Look at the list of node configurations.

The process of reconfiguration depends on the availability of replicas.

Principle of operation⁠

The process of changing the configuration depends on the availability of replicas:

  • if there are no replicas in the cluster — the master node will be stopped while the changes are applied and the cluster will be temporarily unavailable for reading and writing;
  • if there are replicas in the cluster — the cluster will be read and write accessible while the changes are being applied. The replicas will be stopped one by one and the configuration of each replica will be changed. The master node will then switch to one of the replicas and the configuration of the past master node will be changed.

The configuration change time depends on the amount of data in the cluster.

Scale up the cluster⁠

carefully

If you have previously changed the DBMS settings, they may be reset after scaling. Learn more about MySQL sync settings when scaling a cluster.

Scale the cluster when users are least active.

  1. To avoid stopping the master node in a cluster without replicas, add a replica. After scaling is complete, the replica can be removed.

  2. In the Control panel, on the top menu, click Products and select Cloud Databases.

  3. Open the Active tab.

  4. Open the cluster page → Settings tab.

  5. Click Scale Cluster.

  6. Select a different configuration. You can:

    • Select the configuration with the larger disk space only;
    • reduce or increase the number of vCPUs and RAM;
    • change a configuration line with a local disk to another line with a local disk. You can only change a local disk ruler to a network disk ruler and vice versa during cluster recovery.

  7. Optional: increase the number of replicas in the cluster.

  8. Click Save.

  9. After scaling , clear the DNS cache.

  10. Verify that the cluster has scaled correctly.

Clear DNS cache⁠

  1. Open the CLI.

  2. Clear the DNS cache:

    sudo systemctl restart systemd-resolved