Microsoft® SQL Server 2012 Unleashed

Number of Database Snapshots per Source Database

In general, you shouldn’t have too many database snapshots defined on a database because of the copy-on-write overhead each snapshot requires. However, this all depends on the volatility of the source database and a server’s capacity. If there is low volatility and the server is not using much CPU, memory, and disk capacity, this database could more readily support many separate database snapshots at once. If the volatility is high and CPU, memory, and perhaps disk capacity are saturated, you should minimize drastically the number of database snapshots.