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 flash 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. The extra capacity is not visible to the host as available storage.
2. In general, to provision is “to provide” or make something available. Historically, IT departments have overprovisioned IT infrastructure because systems had to be big enough to handle peak demand. That has changed with the growing popularity of cloud computing, however. Today, an administrator can plan around the organization's average needs and simply add cloud services to accommodate occasional usage spikes.