Chapter 17. Using 2-way replication with CephFS
Chapter 17. Using 2-way replication with CephFS To reduce storage overhead with CephFS when data resiliency is not a primary concern, you can opt for using 2-way replication (replica-2). This reduces the amount of storage space used and decreases the level of fault tolerance. There are two ways to use replica-2 for CephFS: Edit the existing default pool to replica-2 and use it with the default CephFS storageclass . Add an additional CephFS data pool with replica-2 . 17.1. Editing the existing default CephFS data pool to replica-2 Use this procedure to edit the existing default CephFS pool to replica-2 and use it with the default CephFS storageclass. Procedure Patch the storagecluster to change default CephFS data pool to replica-2. Check the pool details. 17.2. Adding an additional CephFS data pool with replica-2 Use this procedure to add an additional CephFS data pool with replica-2. Prerequisites Ensure that you are logged into the OpenShift Container Platform web console and OpenShift Data Foundation cluster is in Ready state. Procedure Click Storage StorageClasses Create Storage Class . Select CephFS Provisioner . Under Storage Pool , click Create new storage pool . Fill in the Create Storage Pool fields. Under Data protection policy , select 2-way Replication . Confirm Storage Pool creation In the Storage Class creation form, choose the newly created Storage Pool. Confirm the Storage Class creation. Verification Click Storage Data Foundation . In the Storage systems tab, select the new storage system. The Details tab of the storage system reflect the correct volume and device types you chose during creation
oc patch storagecluster ocs-storagecluster -n openshift-storage --type json --patch '[{ "op": "replace", "path": "/spec/managedResources/cephFilesystems/dataPoolSpec/replicated/size", "value": 2 }]' storagecluster.ocs.openshift.io/ocs-storagecluster patched oc get cephfilesystem ocs-storagecluster-cephfilesystem -o=jsonpath='{.spec.dataPools}' | jq [ { "application": "", "deviceClass": "ssd", "erasureCoded": { "codingChunks": 0, "dataChunks": 0 }, "failureDomain": "zone", "mirroring": {}, "quotas": {}, "replicated": { "replicasPerFailureDomain": 1, "size": 2, "targetSizeRatio": 0.49 }, "statusCheck": { "mirror": {} } } ] ceph osd pool ls | grep filesystem ocs-storagecluster-cephfilesystem-metadata ocs-storagecluster-cephfilesystem-data0