Book Image

Ceph Cookbook

Book Image

Ceph Cookbook

Overview of this book

Ceph is a unified, distributed storage system designed for excellent performance, reliability, and scalability. This cutting-edge technology has been transforming the storage industry, and is evolving rapidly as a leader in software-defined storage space, extending full support to cloud platforms such as Openstack and Cloudstack, including virtualization platforms. It is the most popular storage backend for Openstack, public, and private clouds, so is the first choice for a storage solution. Ceph is backed by RedHat and is developed by a thriving open source community of individual developers as well as several companies across the globe. This book takes you from a basic knowledge of Ceph to an expert understanding of the most advanced features, walking you through building up a production-grade Ceph storage cluster and helping you develop all the skills you need to plan, deploy, and effectively manage your Ceph cluster. Beginning with the basics, you’ll create a Ceph cluster, followed by block, object, and file storage provisioning. Next, you’ll get a step-by-step tutorial on integrating it with OpenStack and building a Dropbox-like object storage solution. We’ll also take a look at federated architecture and CephFS, and you’ll dive into Calamari and VSM for monitoring the Ceph environment. You’ll develop expert knowledge on troubleshooting and benchmarking your Ceph storage cluster. Finally, you’ll get to grips with the best practices to operate Ceph in a production environment.
Table of Contents (18 chapters)
Ceph Cookbook
Credits
Foreword
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Ceph dynamic cluster management


Let's have a quick recap of how clients access the Ceph cluster. To perform a write operation with the Ceph cluster, the client gets the latest copy of the cluster map from the Ceph monitor (if they do not have it already). The cluster map provides information about the Ceph cluster layout. Then the client writes/reads the object, which is stored on a Ceph pool. The pool selects OSDs based on the CRUSH ruleset for that pool. The following diagram illustrates this entire process:

Now, let's understand the process of data storage inside the Ceph cluster. Ceph stores data in logical partitions known as pools. These pools hold multiple PGs, which in turn hold objects. Ceph is a true distributed storage system in which each object is replicated and stored across different OSDs each time. This mechanism has been explained with the help of the following diagram, in which I have tried to present how objects get stored in the Ceph cluster: