Book Image

High Availability MySQL Cookbook

By : Alexander Davies
Book Image

High Availability MySQL Cookbook

By: Alexander Davies

Overview of this book

High Availability is something that all web sites hope to achieve, especially those that are linked to big companies.MySQL, an open source relational database management system (RDBMS), can be made highly available to protect from corruption, hardware failure, software crashes, and user error. Running a MySQL setup is quite simple. Things start getting complex when you start thinking about the best way to provide redundancy. There are a large number of techniques available to add 'redundancy' and 'high availability' to MySQL, but most are both poorly understood and documented.This book will provide you with recipes showing how to design, implement, and manage a MySQL Cluster and achieve high availability using MySQL replication, block level replication, shared storage, and the open source Global File System (GFS).This book covers all the major techniques available for increasing availability of your MySQL databases. It demonstrates how to design, implement, troubleshoot and manage a highly available MySQL setup using any one of several techniques, which are shown in different recipes. It is based on MySQL Cluster 7.0, MySQL (for non clustered recipes) 5.0.77, and CentOS / RedHat Enterprise Linux 5.3.The book starts by introducing MySQL Cluster as a technology and explaining how to set up a simple cluster. It will help you to master the options available for backing up and restoring a file in the MySQL Cluster. By following the practical examples in this book, you will learn how to manage the MySQL Cluster. Further, we will discuss some troubleshooting aspects of the MySQL Cluster.We also have a look at achieving high availability for MySQL databases with the techniques of MySQL Replication, block level replication, shared storage (a SAN or NAS), and DRBD.Finally, you will learn the principles of Performance tuning and tune MySQL database for optimal performance.
Table of Contents (17 chapters)
High Availability MySQL Cookbook
Credits
About the Author
About the Reviewers
Preface
Base Installation
Index

Storage node partitioning and arbitration


In this recipe, we explore what happens when a MySQL Cluster has its storage nodes split into two groups that cannot communicate, but each of which has a full set of cluster data. We will look at this with a practical example, with the explanation of the process in the There's more… section.

Getting ready

In our example lab, nodes 1 and 2 make up nodegroup 0 and nodes 3 and 4 make up nodegroup 1 (look at the output in the recipe Single storage node failure from the SHOW command inside ndb_mgm to see this). In earlier recipes, we have covered what happens if we shut down any combination of nodes, but not what occurs if one node in each nodegroup is isolated from the rest of the cluster.

How to do it…

In our example, we physically isolate node 1 and node 3 from nodes 2, 4, and 5. This means that in effect we are isolating one storage node per nodegroup (with a SQL node running on each) from the other storage nodes (each with a SQL node) and the management...