Book Image

Mastering Ceph

By : Nick Fisk
Book Image

Mastering Ceph

By: Nick Fisk

Overview of this book

Mastering Ceph covers all that you need to know to use Ceph effectively. Starting with design goals and planning steps that should be undertaken to ensure successful deployments, you will be guided through to setting up and deploying the Ceph cluster, with the help of orchestration tools. Key areas of Ceph including Bluestore, Erasure coding and cache tiering will be covered with help of examples. Development of applications which use Librados and Distributed computations with shared object classes are also covered. A section on tuning will take you through the process of optimisizing both Ceph and its supporting infrastructure. Finally, you will learn to troubleshoot issues and handle various scenarios where Ceph is likely not to recover on its own. By the end of the book, you will be able to successfully deploy and operate a resilient high performance Ceph cluster.
Table of Contents (12 chapters)

Tiering modes

There are a number of tiering modes that determine the precise actions of how Ceph reacts to the contents of the HitSets. However, in most cases, the writeback mode will be used. The available modes for use in tiering are writeback, forward, read-forward, proxy, and read-proxy. There are brief descriptions of the available modes and how they act.

Writeback

In writeback mode, data is promoted to the top-level tier by both reads and writes depending on how frequently accessed the object are. Objects in the top-level tier can be modified, and dirty objects will be flushed to the pool at a later date. If an object needs to be read or written to in the bottom tier and the bottom pool supports it, then Ceph will try and directly proxy the operation that has...