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

RBD recovery


In the event that a number of OSDs have failed, and you are unable to recover them via the ceph-object-store tool, your cluster will most likely be in a state where most, if not all, RBD images are inaccessible. However, there is still a chance that you may be able to recover RBD data from the disks in your Ceph cluster. There are tools that can search through the OSD data structure, find the object files relating to RBDs, and then assemble these objects back into a disk image, resembling the original RBD image.

In this section, we will focus on a tool by Lennart Bader to recover a test RBD image from our test Ceph cluster. The tool allows the recovery of RBD images from the contents of Ceph OSDs, without any requirement that the OSD is in a running or usable state. It should be noted that if the OSD has been corrupted due to an underlying file system corruption, the contents of the RBD image may still be corrupt.The RBD recovery tool can be found in the following GitHub repository...