Ceph: Designing and Implementing Scalable Storage Systems

How to do it...

The ceph tell command saves you the effort of logging into the node where the daemon is running. This command goes through the monitor node, so you can execute it from any node in the cluster:

1. The syntax for the ceph tell command is as follows:

        # ceph tell {daemon-type}.{id or *} injectargs           --{config_setting_name} {value}

2. To change the osd_recovery_threads setting from osd.0, execute the following:

        # ceph tell osd.0 injectargs '--osd_recovery_threads=2'

3. To change the same setting for all the OSDs across the cluster, execute the following:

        # ceph tell osd.* injectargs '--osd_recovery_threads=2'

4. You can also change multiple settings as a one liner:

        # ceph tell osd.* injectargs '--osd_recovery_max_active=1  --osd_recovery_max_single_start=1 ...