The Real MTCS SQL Server 2008 Exam 70/432 Prep Kit- P50: Congratulations on your journey to become certified in SQL Server 2008. This book will help prepare you for your exam and give you a practical view of working with SQL Server 2008. | Managing High Availability Chapter 6 227 of setting up the same IP address subnet in two different data centers is extremely complex. With Windows 2008 you now have the option to set up a cluster using different IP address subnets for each site. This makes the process much easier to set up. Configuring Implementing. Combining Solutions In the real world setting up a geographically dispersed cluster is extremely difficult even with the advancements that have been made the clustering software in Windows Server 2008. You may in fact find it easier to combine two of these solutions instead. If you needed to replicate data from a west coast data center to an east coast data center but still maintain a high-availability solution at your primary West Coast data center one configuration you may choose is a cluster on the WEST COAST then use database mirroring to replicate your data from the WEST COAST to the EAST COAST. This would allow you to satisfy the requirements of having a local high-availability solution on the west coast your Windows cluster and still giving you the option of replicating your data to the east coast using database mirroring. In this case you would probably want to use database mirroring in the high performance mode so that your front end application is not slowed down by the WAN link latency between the two sites. When deciding on how to replicate data between sites over a WAN keep in mind that no matter the solution you use data takes approximately three microseconds for every kilometer of fiber cable. A 100 kilometer distance will have a round trip time of approximately 600 microseconds milliseconds . Going from a data center in New York to a data center in Los Angeles and back will take approximately 26 milliseconds. This is in addition to any latency that is added by firewalls encryption devices and the time it takes the storage to actually write the data to the hard drive. To us 26 extra milliseconds is not much but to the SQL server this
