Described herein is a system and method for maintaining cache coherency. The system and method may maintain coherency for a cache memory that is coupled to a plurality of primary storage devices. The system and method may write data to the cache memory and associate the data with a cache generation identification (ID). A different cache generation ID may be associated with each new set of data that is written to the cache memory. The cache generation ID may be written to the primary storage devices. A backup restore operation may be performed on one of the primary storage devices and a backup restore notification may be received. In response to the notification, the system and method may compare the cache generation ID with the generation ID stored on the restored primary storage device and invalidate data stored on the cache memory for the restored primary storage device.