An Introduction to High Availability for Power Systems Running IBM i
Getting started with High Availability for IBM i
Every company faces critical hours when system downtime is unwelcome—whether it’s planned or unplanned. One company’s important hours might only be from 9-to-5, while for another it’s 24×7. Increasingly, shops that were able to accommodate some periods of downtime for backups and system maintenance are finding that this window is quickly shrinking, or has disappeared altogether, because of increased demand for access to applications and data around the clock.
Because of the need to keep systems available for increasing amounts of time, companies are realizing that a system failure or a site disaster would create enormous disruption and expense, especially if it went on for longer than a few hours. For many companies, exposure to this amount of potential downtime
has become unacceptable. Shops that thought they weren’t candidates for a high availability (HA) solution are now realizing an urgent need to start looking at their options.
This white paper provides an introduction to High Availability for Power Systems running IBM i. It is for companies that want to understand the technologies involved and evaluate whether such a solution can become a cost-justifiable component of their backup and recovery strategy. One caveat: Depending on the size and complexity of your information systems, there are many other factors to consider besides the installation of an HA solution when trying to reduce
your vulnerability to planned and unplanned downtime. HA clearly is a significant component in an overall data recovery/system availability strategy, but it often takes a variety of software and even hardware components to provide maximum protection against all exposures to downtime. Before looking at the details of high availability, let’s take a quick look at the cost of downtime and some of the primary strategies that are used to mitigate this cost.
This paper presents an overview of IBM System i high availability to companies that are beginning to explore this powerful business continuity technology. It also walks through the critical components of high availability solutions, including data replication engines, system monitors, role swap capabilities, and the importance of autonomic processes. This paper also looks at the cost of planned and unplanned downtime, and a brief overview of disaster recovery strategies.