Over-Provisioning (OP) technology is a technique used in solid-state drives (SSDs) where a certain portion of the FLASH memory capacity is reserved as spare blocks. This enables the controller to perform garbage collection, wear-leveling, and bad block management more efficiently, thereby extending the lifespan of the SSD. 

To ensure performance stability, consistency, and handle high server workload, enterprise-grade SSDs typically have a relatively large over-provisioning space, usually exceeding 28%. On the other hand, consumer-grade SSDs have relatively less over-provisioning, typically around 7%. The specific allocation ratio varies depending on different applications. The trade-off is that the user-available capacity of the drive is reduced, but the benefits in terms of performance, endurance, and reliability make Over-Provisioning a valuable feature for high-performance and mission-critical storage applications.