Baseline SQL Server and Benchmarking is an important aspect of troubleshooting Disk Storage Performance problems. Not considering certain factors in the planning phase causes problems . Initial analysis assists in this problem. Following are some general areas to consider

Key factors

1.Storage separation

How the indexes and tables are stored is a major determinant of database performance

2.Unused storage

 Unused storage may impact other resources performance. Monitor usage and run regular reports to derive unused storage. Consider redistributing storage .For example , you may have to much disk allocated to a data drive , whereas you may require more space in the Log Directory

 3.Disk I\O separation

 How the demands for disk IO  are managed over a number of storage devices , can have a large impact on how the database manager retrieves data. The database design should consider : disk locations, log file sizes , work files location. . Consider splitting random read and sequential write files , such as MDF and LDF onto separate drives with separate disk controllers.

 4.Unavailable storage space

 Reaching the limit of storage available , can cause a rapid degradation of performance.

Even though in a situation of storage limit – it is critical to add more space or move the database.  Prior to adding any extra  storage space – consider the impact this change will have on   overall performance