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

Setting up storage

When we started discussing the fundamental concepts of clustering, we mentioned that high availability clusters aim, in simple terms, to minimize downtime of services by providing failover capabilities. As we begin the journey of installing a web server and a database server in our cluster, we can't help but wonder how will we synchronize between nodes the content that those services should make available to us. We need to find a way for nodes to share a piece of common storage where data will be saved. If one node fails to provide access to it, the other node will take client requests from then on.

In Linux, a common and cost-free method of dealing with this question is an open source technology known as Distributed Replicated Block Device (DRBD), which makes it possible to mirror or replicate individual storage devices (such as hard disks or partitions) from one node to the other(s) over a network connection. In a somewhat high-level explanation, you can think of the...