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)

Creating an erasure-coded pool

Let's bring our test cluster up again and switch into superuser mode in Linux, so we don't have to keep prepending sudo to our commands.

Erasure-coded pools are controlled by the use of erasure profiles; these controls how many shards each object is broken up into including the split between data and erasure shards. The profiles also include configuration to determine what erasure code plugin is used to calculate the hashes.

The following plugins are available to use:

  • Jerasure
  • ISA
  • LRC
  • SHEC

To see a list of the erasure profiles, run the following command:

    # ceph osd erasure-code-profile ls

You can see there is a default profile in a fresh installation of Ceph:

Let's see what configuration options it contains using the following command:

    # ceph osd erasure-code-profile get default

The default profile specifies that it will use the Jerasure plugin with the...