High Availability System (P.A.S.S) - Choosing a high-availability option - SQL Server 2008

Choosing a high-availability option

You should ask these questions and more when selecting a High Availability option

• What is the Service Level Agreement
• Do they need to protect just a database or the whole SQL Server instance ?
• Are your customers looking for 99.99% uptime?
• Do they require automatic or manual failover capabilities?
• And do they need to protect against a site going offline?

Failover clustering is the best choice to reduce system downtime and provide higher application availability for the whole instance of SQL Server within a site but it does not protect against disk failure and requires a SAN.

Database mirroring is a great choice if there is a need to provide high availability with or without automatic failover on one or more databases within an instance of SQL Server.

If the customer is trying to implement a high-availability or disaster recovery solution with minimal costs and wants multiple standby databases, log shipping would be a perfect fit, since the standby recovery database can span one or more geographical data centers.

You may wish to combine your high availability options to get maximum protection as there isnt one answer to address every requirement.