A company is planning their backup strategy. They intend to implement a grandfather-father-son tape rotation scheme. What is the minimum requirement for tape storage capacity per week?

GFS uses incremental (son) tapes Monday through Thursday, capturing only data that has changed since the last backup - typically a small fraction of total data. Only the Friday (father) tape holds a full backup. Because the four daily incremental tapes combined represent a fraction of the full dataset, the minimum aggregate weekly tape capacity is roughly half the total data size rather than a full copy per day.

Requiring the same size as the data would only be true if a single full backup were run each week with no incrementals; GFS incrementals are far smaller than a full copy.

Two times the server storage capacity grossly overestimates requirements and does not reflect the storage savings achieved by using incremental daily tapes in GFS.

Three times the server storage capacity would apply to a retention scheme requiring multiple simultaneous full copies, which contradicts the efficient rotation model GFS provides.