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Convert a Storage Node to a data-only node

Contributors netapp-lhalbert
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To increase performance, you can convert slower non-ADC Storage Nodes to data-only Storage Nodes.

Using a Storage Node exclusively for data can make sense if your Storage Nodes have differing performance characteristics. For example, to potentially increase performance, you could have data-only, high-capacity spinning-disk Storage Nodes accompanied by metadata-only high-performance Storage Nodes.

Additionally, you can get more metadata capacity by removing low-RAM nodes from Cassandra, which increases the per-node metadata capacity limit. Refer to Manage object metadata storage.

When converting data-only nodes, the grid must contain a minimum of three combined or metadata-only Storage Nodes per site.

Before you begin

  • You are signed in to the Grid Manager using a supported web browser.

  • You have the Maintenance or Root access permission.

  • The Storage Node you want to convert doesn't contain the ADC service, or you have moved the ADC service to another node.

  • The Storage Node isn't a metadata-only node or a data-only node.

  • The Storage Node you want to convert doesn't contain the ADC service, or you have moved the ADC service to another node.

  • There is enough metadata space on other nodes at the site (or you've expanded your grid) to accommodate the metadata that will migrate from the Storage Node you are converting.

    Caution

    • If the metadata that migrates to other nodes on the same site exceeds the size of the metadata reserved space, the grid will become unstable.

    • After you start the conversion, you won't be able to expand the grid.
About this task

Use this procedure to convert one or more combined Storage Nodes that don't contain the ADC service into data-only nodes.

In addition to converting the Storage Node, this procedure decommissions Cassandra from the node. All metadata will migrate to combined or metadata-only Storage Nodes. Depending on the amount of metadata that needs to migrate, this procedure could take up to several days per node to complete.

Tip Generally, you can convert up to 10 nodes at a time if the metadata usage per node is less than 1 TB. If the metadata usage per node is more than 1 TB, convert up to 5 nodes per procedure instead.
Steps

  1. Record the node IDs of the non-ADC Storage Nodes you want to convert.

  2. From the top of the Grid Manager, select the help icon and select API documentation.

  3. Select Go to private API documentation.

  4. Select the POST /private/convert-to-data-only-node/start operation. Refer to Issue API requests for more information.

    Each node will reboot during the procedure.

  5. You can use GET /private/convert-to-data-only-node to monitor the procedure. If errors occur, select POST /private/convert-to-data-only-node/retry to retry the procedure.

  6. Download a recovery package after completing this procedure.