As a general rule, the Planning Tool adds one additional server for high availability for all server roles unless the number ...

As a general rule, the Planning Tool adds one additional server for high availability for all server roles unless the number of servers in the pool is already at the maximum capacity. For example, for a non-virtualized deployment, if you have 80,000 users and 8 Front End Servers in one pool, the Planning Tool will not add an additional server. However, if you have 70,000 users with 7 Front End Servers, the Planning Tool will add one additional server. The Planning Tool also evenly distributes the load across pools. For example, if you have 120,000 users with a total of 12 Front End Servers, the Planning Tool will generate two pools of 6 Front End Servers each and then add one additional server in each pool for a total of 14 servers. If you prefer to optimize for least number of servers, another approach could be to have 1 pool of 8 Front End Servers and the second pool of 5 servers for a total of 13 servers. In this example, you would not need to add the additional Front End Server to the first pool for high availability, only to the second pool. Planning Tool also adds a mirror SQL Database for all databases. For example, if there is a Front End SQL Server database, the Planning Tool will add the other database as the mirror database for this one and name it as the "Front End mirror SQL Server database."