Chapter 1: Preparing for High Availability

Overview

The time :	4 A.M.
The place :	Your bedroom
The event :	Your pager and cellular phone start ringing, buzzing, and vibrating like crazy, waking you from a deep sleep.
The reason :	Your company s mission-critical Microsoft SQL Server is down, and has been for about an hour . The overnight operations staff was unable to bring it online.

Unfortunately, tomorrow is the busiest day of the week and the databases must be fully functional by 8 A.M. Can you not only get there in time, but also bring the server up by then? The last thing that you want to have is the CEO/CTO/CFO/CIO (or other chief ) standing over your shoulder asking you, When will it be up?

Assuming you have a disaster recovery plan in place (which is crucial in any IT organization wanting high availability), the preparation, planning, and testing of that plan can mean the difference between seconds and minutes of downtime versus hours, days, or even weeks. You need to know how long it takes to execute the plan and, more importantly, how to execute it. In addition, if you re facing a truly worst-case disaster recovery scenario for your SQL Server, you need to know how long it would take to restore the database from backups , including the last known good (that means tested ) backup and where it is located.

If this or a similar scenario is your recurring nightmare, the full gravity of making systems and solutions highly available is in the forefront of your mind. If this situation does not speak to you in any way, it might be that stress does not get to you or that you are unaware of the situation s implications. Your employer makes you carry a pager or cellular phone for a reason; he or she wants to be able to get in touch with you day or night in the event something catastrophic happens. There is one driver behind all of this: the risk of losing something critical to the company s business, whether it is revenue, productivity, both revenue and productivity, or an intangible such as industry credibility.