Once you've calculated your cost of downtime and shifted your focus to end-to-end availability, the next step is to select the right technologies to support your critical services. While there are many technologies that can support the always-on, always available extended enterprise -- such as active-active architectures, rapid virtual machine rebooting, application and service monitoring solutions, or cloud-based services, the difficult part is finding an approach that simultaneously supports your availability objectives and also matches what the business is willing to pay to protect critical service. Many enterprises find it useful to group services or applications into tiers of criticality and assign standard recovery time objectives (RTOs) and recovery point objectives (RPOs) as well as service-level agreements (SLAs) for availability. Organizations can then map appropriate technologies to the tiers of criticality using the business requirement.

In the end, the goal of the always-on, always-available enterprise is not 100 percent uptime; rather it is 100 percent service continuity for your most critical services. While there are many companies that have gotten very close, sustaining true 100 percent uptime for any extended period of time is virtually impossible -- there are too many things that can go wrong, from the infrastructure to the applications to natural disasters, human error, or even planned maintenance.

Since some downtime is inevitable, it's important for you to shift your attitude from reacting to downtime toward proactive planning, good processes, and preventive efforts. You may not be able to achieve 100 percent uptime, but you can at least strive to make services available when your customers most need them and have rapid response measures in place to make sure services are brought back online as quickly as possible.