“The Availability Corner” as Published in The Connection

Published by Connect (Formerly ITUG), written by Dr. Bill Highleyman, Paul J. Holenstein, and Dr. Bruce Holenstein

• Testing Your System Recovery Plan (9/2006)
  How the use of active/active technology solves the recovery plan testing syndrome; if recovery from a node failure can be accomplished almost transparently to the users, then node failures can be simulated at will to test the recovery plan.
• Is IBM’s Parallel Sysplex a NonStop Competitor? (6/2006)
  A comparison of HP’s NonStop and IBM’s Parallel Sysplex that are the primary industry offerings tolerating single failures that lead to very high levels of availability.
• Grid Computing (3/2006)
  How grid computing seeks to standardize the use of disparate systems in a computing utility that would manage all of the resources available to it as a set of services to improve reliability, availability, business agility, security, and a better return on IT investment.
• The Net Present Value of Active/Active Systems (1/2006)
  A review of the sum of the present values of expenditure for a multi-node active/active system today and its return of investment, called the net present value (NPV).
• TCO for Active/Active Systems (11/2005)
  How cost, understanding, and optimizing the total cost of ownership (TCO) of an active/active system is much more involved than it is for standard monolithic systems.
• Fault Tolerance vs. High Availability (9/2005)
  A comparison of the factors that differentiate fault-tolerant systems from high-availability systems, with the length of recovery time as the secret to high availability.
• The Great Tape Backup Paradigm Shift (7/2005)
  A reconsideration of the way in which systems are backed-up, since recovery time is what matters when making an application available after an outage.
• The Language of Availability (5/2005)
  A glossary of several terms defining reliability and the systems that are used in these articles.
• What Reliability Do We Really Need? (1/2005)
  A review about how adding expensive redundant hardware when striving for higher reliability benefits only two of three areas: high reliability, high performance, or low cost.
• Let’s Measure System Reliability in Centuries (11/2004)
  This series of Availability Column articles focuses on how to achieve a high level of availability at little additional cost.