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

CRUSH tunables


In Ceph, developers calculate the placement of data by making an enhancement to the CRUSH algorithm. Developers have introduced a series of CRUSH tunable options to support the change in behavior. These options control the improved variation or legacy of the algorithm that is used. Both Ceph servers and clients must support the new version of CRUSH for using new tunables.

Hence, Ceph developers have named CRUSH tunable profiles in the name of the Ceph version in which they were introduced. For example, the Firefly release supports the firefly tunables that will not work with the older clients. The ceph-osd and ceph-mon will prevent older clients from connecting to the cluster, as soon as a given set of tunables are changed from the legacy default behavior. These old clients do not support the new CRUSH features.

For more information, please visit http://docs.ceph.com/docs/jewel/rados/operations/crush-map/#tunables.

The evolution of CRUSH tunables

In the following section, we will...