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Scale a MySQL sync cluster

The MySQL sync Managed Database cluster can be scaled. For example:

  • increase vCPU and RAM to improve cluster performance;
  • change the configuration line with local disk to another line with local disk — the disk size must be larger than in the previous configuration, and you can reduce or increase the number of vCPUs and RAM. You can change the line with a local disk to a line with a network volume and vice versa only during cluster recovery.

View the list of node configurations.

The configuration change process depends on whether replicas exist.

How it works

The configuration change process depends on whether replicas exist:

  • if the cluster has no replicas, the master node will be stopped while changes are being applied, and the cluster will be temporarily unavailable for read and write operations;
  • if the cluster has replicas, the cluster will remain available for read and write operations while changes are being applied. Replicas will be stopped one by one, and the configuration of each will be changed. Then, the master node will switch to one of the replicas, and the configuration of the former master node will be changed.

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

Scale the cluster

warning

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

Scale your cluster when user activity is at its lowest.

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

  2. In the Dashboard, on the top menu click Products and select Managed Databases.

  3. Open the Active tab.

  4. Open the cluster page → Settings tab.

  5. Click Change configuration.

  6. Select a different configuration. You can:

    • select a configuration with a larger disk size only;
    • decrease 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 line to a network volume line 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 been scaled correctly.

Clear DNS cache

  1. Open the CLI.

  2. Clear the DNS cache:

    sudo systemctl restart systemd-resolved