Book Image

Ceph: Designing and Implementing Scalable Storage Systems

By : Michael Hackett, Vikhyat Umrao, Karan Singh, Nick Fisk, Anthony D'Atri, Vaibhav Bhembre
Book Image

Ceph: Designing and Implementing Scalable Storage Systems

By: Michael Hackett, Vikhyat Umrao, Karan Singh, Nick Fisk, Anthony D'Atri, Vaibhav Bhembre

Overview of this book

This Learning Path takes you through the basics of Ceph all the way to gaining in-depth understanding of its advanced features. You’ll gather skills to plan, deploy, and manage your Ceph cluster. After an introduction to the Ceph architecture and its core projects, you’ll be able to set up a Ceph cluster and learn how to monitor its health, improve its performance, and troubleshoot any issues. By following the step-by-step approach of this Learning Path, you’ll learn how Ceph integrates with OpenStack, Glance, Manila, Swift, and Cinder. With knowledge of federated architecture and CephFS, you’ll use Calamari and VSM to monitor the Ceph environment. In the upcoming chapters, you’ll study the key areas of Ceph, including BlueStore, erasure coding, and cache tiering. More specifically, you’ll discover what they can do for your storage system. In the concluding chapters, you will develop applications that use Librados and distributed computations with shared object classes, and see how Ceph and its supporting infrastructure can be optimized. By the end of this Learning Path, you'll have the practical knowledge of operating Ceph in a production environment. This Learning Path includes content from the following Packt products: • Ceph Cookbook by Michael Hackett, Vikhyat Umrao and Karan Singh • Mastering Ceph by Nick Fisk • Learning Ceph, Second Edition by Anthony D'Atri, Vaibhav Bhembre and Karan Singh
Table of Contents (27 chapters)
Title Page
About Packt
Contributors
Preface
Index

Monitoring Ceph MDS


Ceph MDS servers manage CephFS filesystems. A Ceph MDS server can be in various states including up, down, active, and inactive. An MDS server should always be up and active when it is in a correct and functioning state.

There are two main commands we can use to monitor an operational MDS cluster. We use mds stat to get a quick insight into the present state of MDSs. You might recognize this output format as the same one presented by the Ceph status fsmap key.

root@ceph-client0:~# ceph mds stat
e38611: 1/1/1 up {0=ceph-mds0=up:active}

If we would like the detailed output of the MDS map of a given cluster, we can use the mds dump subcommand. Like all other subcommands containing dump, it prints the entire MDS map, which contains detailed information about active MDS daemons as well as other stats.

root@ceph-client0:~# ceph mds dump
dumped fsmap epoch 38611
fs_name cephfs
epoch 38611
flags 0
created 2017-09-10 20:20:28.275607
modified 2017-09-10 20:20:28.275607
tableserver...