Allowance for Future Database Growth
To accommodate the growth of the data warehouse over time, use the following guidelines.
In general, if the initial data warehouse size is based on transactions over the last three years, expect a data warehouse size growth over the coming three years to be of the same size as the initial data warehouse size. If the expected transaction volumes for the customer increase, then you should make extra allowance.
If the initial data warehouse is created based on the last 3 years of activity, and the initial size is 250 GB, then expect the data warehouse size to at least double over the coming 3 years.
Hence, estimate of Disk Space Allocation to allow for medium-term data warehouse growth = 2 * (initial database size estimate) = 2 *((X)*100).