ODF 4.15 | Migration of existing OSD to the optimized OSD in OpenShift Data Foundation for Regional-DR cluster - Technology Preview

The knowledgebase article outlines the procedure for optimizing an existing OpenShift Data Foundation cluster for Regional-DR. The process for this technology preview feature involves sequentially migrating each Object Storage Daemon (OSD) to the new store type and ensuring data integrity throughout the process.

The document also covers the troubleshooting steps if there is an error observed during the OSD migration.

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Prerequisites

• Ensure that the Hub cluster and the two Managed clusters are all on the same OpenShift Data Foundation version 4.15.
• Ensure that the OpenShift Data foundation clusters are running with non-optimized OSDs.
• Access to an OpenShift Container Platform environment with administrative privileges.

Procedure

1. On the Primary and Secondary Managed cluster, navigate to Storage -> Data Foundation -> Storage Systems -> Block and File tab.

2. In the Details card, check the Disaster recovery readiness status.

   For existing clusters that are not using optimized OSDs, the status shows as Pending.

3. Click on Prepare cluster for DR setup link next to Pending status.

4. Click Yes, migrate OSDs to continue with migrating the OSDs and optimizing the cluster.

   When the OSD migration starts, the status of Disaster recovery readiness changes to In progress and you can view the status of the number of OSDs migrated on the health Status card.

   NOTE: This process may take longer if the volume of data is large.

   When the migration completes, the health Status will show a green tick with the message “Cluster ready for Regional-DR setup.” and the status of Disaster recovery readiness changes to Completed with green tick.

5. After migration completes, go to the Hub cluster and create the DRPolicy.
   If you were previously on the Create DRPolicy page, then perform a hard refresh on this page to remove the error messages and continue with creating the DRPolicy. See Creating Disaster Recovery Policy on Hub cluster

Troubleshooting cluster migration issues

During the migration, if you experience issues during OSD disk cleanup or prolonged data rebalancing, follow this procedure:

1. Pause the migration by stopping the rook operator

   oc -n openshift-storage scale deployment rook-ceph-operator --replicas=0
   

2. Manually intervene to resolve the issue with the OSD or the data rebalancing process.

3. Once the issue is resolved, start the Rook operator again:

   oc -n openshift-storage scale deployment rook-ceph-operator --replicas=1