Setting Ceph OSD full thresholds by using the ODF CLI tool

Use this procedure to set Ceph OSD full thresholds temporarily by using the ODF CLI tool.

Prerequisites

Whenever the cluster reaches its full state, it is required to immediately increase the thresholds. With the ODF CLI tool, you can effectively manage and troubleshoot your Fusion Data Foundation environment from a terminal. For more information about the compatible version details and to download the CLI, see customer portal.

Procedure

Use the set command to adjust Ceph full thresholds. The set command supports the full, backfillfull, and nearfull subcommands. See the following examples for how to use each subcommand.

full

Use this subcommand to update the full ratio of Ceph OSDs when Ceph prevents the IO operation on OSDs that reached the specified capacity. The default value is 0.85.

Important: Do not set the full ratio value of OSDs too close to 1.0 because the cluster becomes unrecoverable if the OSDs are full and have nowhere to grow.

For example, run the following command to set the full ratio to 0.90:

$ odf set full 0.90

backfillfull

Use this subcommand to update the backfillfull ratio of Ceph OSDs when Ceph denies backfilling to the OSDs that reached the specified capacity. The default value is 0.80.

Important: If the value is set too close to 1.0, the OSDs become full and prevent the cluster from backfilling.

For example, run the following command to set the backfillfull ratio to 0.85:

$ odf set backfillfull 0.85

nearfull

Use this subcommand to update the nearfull ratio of Ceph OSDs when the cluster reaches the specified capacity and Ceph returns the nearfull message of OSDs. The default value is 0.75.

For example, run the following command to set the nearfull ratio to 0.80:

$ odf set nearfull 0.80