Book Image

Mastering Ceph - Second Edition

By : Nick Fisk
Book Image

Mastering Ceph - Second Edition

By: Nick Fisk

Overview of this book

Ceph is an open source distributed storage system that is scalable to Exabyte deployments. This second edition of Mastering Ceph takes you a step closer to becoming an expert on Ceph. You’ll get started by understanding the design goals and planning steps that should be undertaken to ensure successful deployments. In the next sections, you’ll be guided through setting up and deploying the Ceph cluster with the help of orchestration tools. This will allow you to witness Ceph’s scalability, erasure coding (data protective) mechanism, and automated data backup features on multiple servers. You’ll then discover more about the key areas of Ceph including BlueStore, erasure coding and cache tiering with the help of examples. Next, you’ll also learn some of the ways to export Ceph into non-native environments and understand some of the pitfalls that you may encounter. The book features a section on tuning that will take you through the process of optimizing both Ceph and its supporting infrastructure. You’ll also learn to develop applications, which use Librados and distributed computations with shared object classes. Toward the concluding chapters, you’ll learn to troubleshoot issues and handle various scenarios where Ceph is not likely to recover on its own. By the end of this book, you’ll be able to master storage management with Ceph and generate solutions for managing your infrastructure.
Table of Contents (18 chapters)
Free Chapter
1
Section 1: Planning And Deployment
6
Section 2: Operating and Tuning
13
Section 3: Troubleshooting and Recovery

Extremely slow performance or no IO

If your cluster is performing really slowly, to the point that it is barely servicing IO requests, there is probably an underlying fault or configuration issue. These slow requests will likely be highlighted on the Ceph status display with a counter for how long the request has been blocked. There are a number of things to check in this case.

Flapping OSDs

Check ceph.log on the monitors, and see whether it looks like any OSDs are flapping up and down. When an OSD joins a cluster, its PGs begin peering. During this peering process, IO is temporarily halted, so in the event of a number of OSDs flapping, the client IO can be severely impacted. If there is evidence of flapping OSDs, the next...