Home > Storage > PowerMax and VMAX > Storage Admin > Dell PowerMax: Data Reduction > Deduplication algorithm
The SHA-256 algorithm generates a 32-byte code for each 32KB block of data. Consider a system with 1 PB of written data with 5% updated per day. In 1 million years of operation, there is a 20% likelihood of a hash collision. As each 128KB track is handled as 4 blocks of 32KB there would need to be a hash collision on all four blocks in the same 128KB track to have an actual hash collision. The odds of having all 4 collide makes this only theoretical (less than a 1% chance in a trillion years of operation).