High Availability IT Services

This book starts with the basic premise that a service is comprised of the 3Ps—products, processes, and people. Moreover, these entities and their sub-entities interlink to support the services that end users require to run and support a business. This widens the scope of any availability design far beyond hardware and software. It also increases the potential for service failure for reasons beyond just hardware and software; the concept of logical outages.High Availability IT Services details the considerations for designing and running highly available "services" and not just the systems infrastructure that supports those services. Providing an overview of virtualization and cloud computing, it supplies a detailed look at availability, redundancy, fault tolerance, and security. It also stresses the importance of human factors.The book starts off by providing an availability primer and detailing the reasons why you need to be concerned with high availability. Next, it outlines the theory of reliability and availability and the elements of actual practices in this high availability (HA) area, including Service Level Agreements (SLAs) and Change Management.Examining what the major hardware and software vendors have to offer in the HA world, the book considers the ubiquitous world of clouds and virtualization as well as the availability considerations they present.The book examines high availability concepts and architectures such as reliability, availability, and serviceability (RAS); clusters; grids; and redundant arrays of independent disks (RAID) storage. It also covers the role of security in providing high availability, cluster offerings, emergent Linux clusters, online transaction processing (OLTP), and relational databases.