Overprovisioning, sometimes spelled over-provisioning, is the inclusion of extra storage capacity in a flash solid state drive (SSD). The extra capacity is not visible to the host as available storage.
SSD overprovisioning can increase the endurance of a solid state drive by distributing the total number of writes and erases across a larger population of NAND blocks and pages over time. It can also improve performance by giving the flash controller additional buffer space for managing program/erase (P/E) cycles and improving the probability that a write operation will have immediate access to a pre-erased block.
To provision is “to provide” or make something available.