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

Using the ceph tell command


Another efficient way to change the runtime configuration for the Ceph daemon without the overhead of logging in to that node is to use the ceph tell command.

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}
  1. To change the osd_recovery_threads setting from osd.0, execute the following:
     # ceph tell osd.0 injectargs '--osd_recovery_threads=2'
  1. To change the same setting for all the OSDs across the cluster, execute the following:
        # ceph tell osd.* injectargs '--osd_recovery_threads=2'
  1. 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 --osd_recovery_op_priority...