1. A system for capacity management in a deduplication computing storage environment, comprising: at least one processor device, operable in the deduplication computing storage environment, wherein the at least one processor device is adapted for: estimating a deduplication storage capacity as a function of an expected deduplication ratio, the expected deduplication ratio being an aggregation of a current deduplication ratio and a configured deduplication ratio, the current deduplication ratio depending on data currently stored in deduplication storage, the configured deduplication ratio being an estimate made at a configuration stage of the deduplication computing storage environment, wherein the at least one processor device is further adapted for estimating the deduplication storage capacity includes estimating Scapacity as a function of Pcapacity, Pconsumed, Rexpected, and Dnominal, where Scapacity is the deduplication storage capacity, Pcapacity is a physical storage capacity of the deduplication storage environment, Pconsumed is an amount of physical storage consumed in the deduplication storage environment, Rexpected is the expected deduplication ratio, and Dnominal is a nominal size of data currently stored in the deduplication storage environment.