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

Tuning the Linux kernel IO


In this recipe, we will get started by showing the tools that can be used to monitor the Input/Output (IO) from a block device. We will then show how to tune the way that the Linux Kernel handles IO to meet your requirements in the best possible manner and finally explain how the Kernel handles IO requests in a little bit more detail.

Getting ready

In this section, we will see how to monitor the IO characteristics of your system using commands that will come installed on a RedHat or CentOS system.

The first command for monitoring IO is a command used most often for other things and it is called top. Running top and pressing 1 to show per-CPU statistics will give you an idea of what your CPUs are doing. Most importantly, in this context, the wa column shows what percentage of time the CPU is spending waiting for IO operations to be completed.

In systems that are very IO-bound, this I/O waiting figure can effectively be 100 percent, which means that the CPUs in the...