what is scale out deployment in ssrs .. when we need to go for it .. how to configure it ? can you explain me thank you

A Reporting Services scale-out deployment is one that allows you to have multiple report server instances that share a single report server database. Please go through the following for more details and let us know if you have any questions. http://msdn.microsoft.com/en-us/library/ms181357.aspx http://technet.microsoft.com/en-us/library/ms159114.aspx