Virtual NAND capacity extension in a hybrid drive

A method and system for virtual cache memory extension in a data storage device are disclosed herein. The storage device may include a memory that serves as a cache to a primary memory. The method for the storage device may include maintaining mapping information of one or more logical block addresses associated with data stored in the cache memory and maintaining mapping information of one or more logical block addresses associated with data not stored in the cache memory. Data stored in the cache memory may be selected for eviction when the available capacity of the cache memory changes, e.g., due to storing resume data in a hibernate operation. Data selected for eviction may be transferred to the primary memory but still tracked as being part of a virtual extended cache, and thus can be quickly restored into the cache memory when the resume data is no longer needed.