Chapter 21. Setting Ceph OSD full thresholds You can set Ceph OSD full thresholds using the ODF CLI tool or by updating the StorageCluster CR. 21.1. Setting Ceph OSD full thresholds using the ODF CLI tool You can set Ceph OSD full thresholds temporarily by using the ODF CLI tool. This is necessary in cases when the cluster gets into a full state and the thresholds need to be immediately increased. Prerequisites Download the OpenShift Data Foundation command line interface (CLI) tool. With the Data Foundation CLI tool, you can effectively manage and troubleshoot your Data Foundation environment from a terminal. You can find a compatible version and download the CLI tool from the customer portal . Procedure Use the set command to adjust Ceph full thresholds. The set command supports the subcommands full , backfillfull , and nearfull . See the following examples for how to use each subcommand. full This subcommand allows updating the Ceph OSD full ratio in case Ceph prevents the IO operation on OSDs that reached the specified capacity. The default is 0.85 . Note If the value is set too close to 1.0 , the cluster becomes unrecoverable if the OSDs are full and there is nowhere to grow. For example, set Ceph OSD full ratio to 0.9 and then add capacity: For instructions to add capacity for you specific use case, see the Scaling storage guide . If OSDs continue to be in stuck , pending , or do not come up at all: Stop all IOs. Increase the full ratio to 0.92 : Wait for the cluster rebalance to happen. Once cluster rebalance is complete, change the full ratio back to its original value of 0.85: backfillfull This subcommand allows updating the Ceph OSDd backfillfull ratio in case Ceph denies backfilling to the OSD that reached the capacity specified. The default value is 0.80 . Note If the value is set too close to 1.0 , the OSDs become full and the cluster is not able to backfill. For example, to set backfillfull to 0.85 : nearfull This subcommand allows updating the Ceph OSD nearfull ratio in case Ceph returns the nearfull OSDs message when the cluster reaches the capacity specified. The default value is 0.75 . For example, to set nearfull to 0.8 : 21.2. Setting Ceph OSD full thresholds by updating the StorageCluster CR You can set Ceph OSD full thresholds by updating the StorageCluster CR. Use this procedure if you want to override the default settings. Procedure You can update the StorageCluster CR to change the settings for full , backfillfull , and nearfull . full Use this following command to update the Ceph OSD full ratio in case Ceph prevents the IO operation on OSDs that reached the specified capacity. The default is 0.85 . Note If the value is set too close to 1.0 , the cluster becomes unrecoverable if the OSDs are full and there is nowhere to grow. For example, to set Ceph OSD full ratio to 0.9 : backfillfull Use the following command to set the Ceph OSDd backfillfull ratio in case Ceph denies backfilling to the OSD that reached the capacity specified. The default value is 0.80 . Note If the value is set too close to 1.0 , the OSDs become full and the cluster is not able to backfill. For example, set backfill full to 0.85 : nearfull Use the following command to set the Ceph OSD nearfull ratio in case Ceph returns the nearfull OSDs message when the cluster reaches the capacity specified. The default value is 0.75 . For example, set nearfull to 0.8 :

Commands:
odf set full 0.9
odf set full 0.92
odf set full 0.85
odf set backfillfull 0.85
odf set nearfull 0.8
oc patch storagecluster ocs-storagecluster -n openshift-storage --type json --patch '[{ "op": "replace", "path": "/spec/managedResources/cephCluster/fullRatio", "value": 0.90 }]'
oc patch storagecluster ocs-storagecluster -n openshift-storage --type json --patch '[{ "op": "replace", "path": "/spec/managedResources/cephCluster/backfillFullRatio", "value": 0.85 }]'
oc patch storagecluster ocs-storagecluster -n openshift-storage --type json --patch '[{ "op": "replace", "path": "/spec/managedResources/cephCluster/nearFullRatio", "value": 0.8 }]'