Metadata servers are used only for CephFS, which is not production ready at the time of writing this book. A metadata server has several states, such as UP, DOWN, ACTIVE, and INACTIVE. While performing monitoring of MDS, you should make sure that the state of MDS is UP and ACTIVE. The following commands will help you get information related to Ceph MDS.
To check the MDS status, execute:
# ceph mds stat
To display the details of the metadata server, execute:
# ceph mds dump
The output is shown in the following screenshot: