Western Digital Technologies, Inc.

Avago Technologies General IP (Singapore) Pte. Ltd.

Karimulla Sheik

Sumanesh Samanta

Kapil Sundrani

Sujan Biswas

Debal Krishna Mridha

Mohana Rao Goli

Naga S Vadalamani

Naga Shankar Vadalamani

A storage device and methods of operation are disclosed. The device comprises a controller configured to execute a read command, a write command, a first vendor specific command, and a second vendor specific command, and further comprises a persistent memory and a non-persistent memory. When executing the first vendor specific command, the device begins operation in a first vendor specific mode. In this mode, the device stores write data in the non-persistent memory and does not immediately commit the write data to persistent memory. When executing the second vendor specific command, the device begins operation in a second vendor specific mode. In this mode, the device immediately commits write data to persistent memory. The first vendor specific mode is ideal when power supplies are healthy and redundant, while the second vendor specific mode is ideal when power supplies are not redundant and/or healthy.

Keeping a zone random write area in non-persistent memory

Example storage systems, storage devices, and methods provide a write group journal for identifying incomplete writes. Related write request indicators are stored in a non-volatile journal in a solid state drive to identify a related write group and indicate whether the related write group has been stored in storage locations corresponding to physical page addresses. As the write requests for the related write group are processed, the related write request indicator is updated to allow incomplete write groups to be identified in the event of a failure.

Incomplete write group journal

Example storage systems, storage devices, and methods provide a write group journal for identifying incomplete writes. Related write request indicators are stored in a non-volatile journal in a solid state drive to identify a related write group and indicate whether the related write group has been stored in storage locations corresponding to physical page addresses. An event notification is sent to a host system when the related write request indicator indicates that the group was incomplete at the time of a data loss event.

A system and method for managing the life expectancy of at least one solid state drive (SSD) within a cache device of a storage subsystem includes determining a baseline rate of decline for each SSD based on its guaranteed life expectancy. At intervals, each SSD of the cache device is polled for remaining life and power-on time, and a current rate of decline (based on time since initialization) and a cumulative rate of decline (based on total lifespan of the SSD) is determined. When both the current rate of decline and the cumulative rate of decline exceed the baseline rate of decline for any SSD of the cache device, write requests to that SSD are blocked and redirected to the virtual device until either the current rate of decline or cumulative rate of decline drop below the baseline rate.

System and method of life management for low endurance SSD NAND devices used as secondary cache

System and techniques for rebuilding a redundant secondary storage cache including a first storage device and a second storage device are described. A metadata entry indicative of a validity of a portion of information stored by a first storage cache device and associated with a region of a primary storage device is received. When the validity of the portion of information associated with the region of the primary storage device is established, a region lock is requested on the region of the primary storage device associated with the portion of information stored by the first storage cache device. Then, the portion of information and the corresponding metadata entry associated with the region of the primary storage device is copied from the first cache storage device to a second storage cache device to rebuild the second storage cache device.

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Bengaluru, India

Karimulla Sheik