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Enable and manage ONTAP FlexCache write-back

Contributors netapp-dbagwell elliott-ecton netapp-lenida
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Beginning with ONTAP 9.15.1, you can enable FlexCache write-back mode on FlexCache volumes to provide better performance for edge computing environments and caches with write-heavy workloads. You can also determine whether write-back is enabled on a FlexCache volume or disable write-back on the volume when necessary.

When write-back is enabled on the cache volume, write requests are sent to the local cache rather than to the origin volume.

Before you begin

You must be in advanced privilege mode.

Create a new FlexCache volume with write-back enabled

Steps

You can create a new FlexCache volume with write-back enabled by using ONTAP System Manager or the ONTAP CLI.

System Manager

  1. If the FlexCache volume is on a different cluster than the origin volume, create a cluster peer relationship:

    1. On the local cluster, click Protection > Overview.

    2. Expand Intercluster Settings, click Add Network Interfaces, and add intercluster interfaces to the cluster.

      Repeat this on the remote cluster.

    3. On the remote cluster, click Protection > Overview. Click Menu options icon in the Cluster Peers section and click Generate Passphrase.

    4. Copy the generated passphrase and paste it in the local cluster.

    5. On the local cluster, under Cluster Peers, click Peer Clusters and peer the local and remote clusters.

  2. If the FlexCache volume is on a different cluster than the origin volume, create an SVM peer relationship:

    Under Storage VM Peers, click Menu options icon and then Peer Storage VMs to peer the storage VMs.

    If the FlexCache volume is on the same cluster, you cannot create an SVM peer relationship using System Manager.

  3. Select Storage > Volumes.

  4. Select Add.

  5. Select More Options and then select Add as cache for a remote volume.

  6. Select Enable FlexCache write-back.

Enable FlexCache write-back on an existing FlexCache volume

You can enable FlexCache write-back on an existing FlexCache volume using ONTAP System Manager or the ONTAP CLI.

System Manager

  1. Select Storage > Volumes and select an existing FlexCache volume.

  2. On the volume's Overview page, click Edit in the upper right corner.

  3. In the Edit Volume window, select Enable FlexCache write-back.

Check if FlexCache write-back is enabled

Steps

You can use System Manager or the ONTAP CLI to determine whether FlexCache write-back is enabled.

System Manager

  1. Select Storage > Volumes and select a volume.

  2. In the volume Overview, locate FlexCache details and check if FlexCache write-back is set to Enabled on the FlexCache volume.

Disable write-back on a FlexCache volume

Before you can delete a FlexCache volume you need to disable FlexCache write-back.

Steps

You can use System Manager or the ONTAP CLI to disable FlexCache write-back.

System Manager

  1. Select Storage > Volumes and select an existing FlexCache volume that has FlexCache write-back enabled.

  2. On the volume's Overview page, click Edit in the upper right corner.

  3. In the Edit Volume window, deselect Enable FlexCache write-back.