Brady Reiter, General Manager of Enterprise Architecture and Application Strategy at NaviSite (, says:

NaviSite has been managing packaged and custom applications for over a decade. During my eight years with NaviSite I have talked with many companies about the common causes of application downtime. A re-occurring theme has surfaced which data center/IT managers need to take to heart, and that is business and IT often have different definitions of zero downtime. In order to achieve zero downtime for your business users they expect not only that the servers are up and running but that all areas of the application are working properly. If your company can’t complete its month end processes or performance is degraded then in your business user’s eyes you have not achieved zero downtime.