Many are the myths and misunderstandings that surround high availability. Typically, they appear as variations on four basic misconceptions: It’s costly It’s complicated It’s hard to measure It’s hard to test These false impressions persist partly because hardware vendors continue to aggressively press their own agendas. Erroneous messaging has led many IT managers to believe that clustering applies only to mission-critical applications. The truth is that if your organization cannot tolerate even minutes of planned or unplanned downtime for its business-critical applications, there are powerful high availability solutions within economic reach. They mitigate against the primary threats to the continuity of your business: human error, application failure, computer failures, routine or scheduled maintenance, or complete site outages. Before we get down to debunking our four myths, let’s step back and take a high-level look at high availability.