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

Installing DRBD on two Linux servers


In this recipe, we will take two freshly installed CentOS 5.3 servers and configure DRBD to synchronize a LVM logical volume on both nodes, running MySQL. We will demonstrate how to manually failover the service.

Getting ready

Ensure that both nodes are freshly installed and, if possible, have a clean kernel. When you install MySQL, ensure that you are not allocating all of the space to the / logical volume (the default in the CentOS / RHEL installer Anaconda). You can either create the LVM logical volume that DRBD will use during setup, or leave the space unallocated in a volume group and create the logical volume later. You can check the space available in a volume group using the vgs command:


[root@node3 ~]# vgs
  VG     #PV #LV #SN Attr   VSize  VFree 
  system   1   2   0 wz--n- 25.00G 15.25G

This shows that the volume group system has just over 15G spare space, which is sufficient for this test.

Ensure that both nodes have the CentOS "Extras" repository...