Book Image

CentOS High Performance

By : Gabriel Cánepa
Book Image

CentOS High Performance

By: Gabriel Cánepa

Overview of this book

CentOS is the enterprise level Linux OS, which is 100% binary compatible to Red Hat Enterprise Linux (RHEL). It acts as a free alternative to RedHat's commercial Linux offering, with only a change in the branding. A high performance cluster consists in a group of computers that work together as one set parallel, hence minimizing or eliminating the downtime of critical services and enhancing the performance of the application. Starting with the basic principles of clustering, you will learn the necessary steps to install a cluster with two CentOS 7 servers. We will then set up and configure the basic required network infrastructure and clustering services. Further, you will learn how to take a proactive approach to the split-brain issue by configuring the failover and fencing of the cluster as a whole and the quorum of each node individually. Further, we will be setting up HAC and HPC clusters as a web server and a database server. You will also master the art of monitoring performance and availability, identifying bottlenecks, and exploring troubleshooting techniques. At the end of the book, you’ll review performance-tuning techniques for the recently installed cluster, test performance using a payload simulation, and learn the necessary skills to ensure that the systems, and the corresponding resources and services, are being utilized to their best capacity.
Table of Contents (13 chapters)
CentOS High Performance
About the Author
About the Reviewers

Moving to an A/A cluster

As you will recall from the introduction of Chapter 3, A Closer Look at High Availability, A/A clusters tend to provide higher availability as several nodes are actively running applications at the same time (which, by the way, requires that the necessary data for those applications be available simultaneously on all cluster members). The downside is that if one or more nodes go offline, the remaining ones are assigned extra processing load, thus negatively impacting the overall performance of the cluster.

That being said, let's examine briefly the required steps to convert our current A/P cluster to an A/A one. Make sure a STONITH resource has been defined (refer to chapter 3 for further details).

  1. Enable STONITH resource by using the following command:

    pcs property set stonith-enabled=trueInstall
  2. Install the additional software that will be needed for this:

    yum update && yum install gfs2-utils dlm

    As opposed to a traditional journaling filesystem such as ext4...