The average employee today checks e-mail once every 15 minutes, with some users checking e-mail as often as 40 times per hour. In addition, the growing use of personal mobile devices means that employees have become literally attached to their e-mail at all times, with some checking their device as soon as each e-mail message arrives. Now that e-mail has evolved into a critical business communications tool, employees have come to expect access to their e-mail 24/7, with very little tolerance for downtime.
Meeting the "always on" expectations of employees creates challenges for the IT administrator. Service-level agreements (SLAs) are increasingly stringent and demanding as users require non-stop access to e-mail and other collaborative features of Microsoft Exchange. Availability of Exchange is paramount, as well as protecting the integrity of your Exchange data. In order to maintain Exchange availability, every component of the Exchange infrastructure needs to be considered. You can protect your mailbox server to the highest degree but if your Domain Name System (DNS) server fails, the Exchange server may not be accessible.
To help your company protect its Exchange environment, there are a series of steps you can follow to achieve optimal Exchange availability. The tips are designed to help identify what availability levels should be designated in order to achieve Exchange SLA commitments with fewer resources and lower costs.
Define availability objectives
Creating availability objectives is an important first step in formulating Exchange protection strategies. This is typically done by establishing a Recovery Time Objective (RTO) and a Recovery Point Objective (RPO) for your Exchange environment. RTO is the time it takes for an application to be running again, while RPO is the point in time to which the IT professional can recover data in case of a failure.
RTO and RPO baselines establish the SLAs you commit to for the overall company, business units or specific internal groups. You may even have different Exchange SLAs for different users within your company. For example, you may have an executive group that requires 24/7 e-mail access while the rest of the company can withstand Exchange downtime of up to one hour. In addition, consideration should be given to what level of protection is needed for the other components of your Exchange infrastructure such as Active Directory and DNS servers.