Storage class memory (SCM) memory mode cache system
An SCM memory mode NVDIMM-N cache system includes an SCM subsystem, and an NVDIMM-N subsystem having at volatile memory device(s) and non-volatile memory device(s). A memory controller writes data to the volatile memory device(s) and, in response, updates a cache tracking database. The memory controller then writes a subset of the data to the SCM subsystem subsequent to the writing of that data to the volatile memory device(s) and, in response, updates the cache tracking database. The memory controller then receives a shutdown signal and, in response, copies the cache tracking database to the volatile memory device(s) in the NVDIMM-N subsystem. The NVDIMM-N subsystem then copies at least some of the data and the cache tracking database from the volatile memory device(s) to the non-volatile memory device(s) prior to shutdown. The data and the cache tracking database may then be retrieved from non-volatile memory device(s) when the system is restored.
1. A Storage Class Memory (SCM) memory mode Non-Volatile Dual Inline Memory Module (NVDIMM-N) cache system, comprising:
a Storage Class Memory (SCM) subsystem;
a Non-Volatile Dual Inline Memory Module (NVDIMM-N) subsystem including at least one volatile memory device and at least one non-volatile memory device; and
a memory controller that is coupled to the SCM subsystem and the NVDIMM-N subsystem, wherein the memory controller is configured to:
write a plurality of data to the at least one volatile memory device in the NVDIMM-N subsystem and, in response, update a cache tracking database;
write a first subset of the plurality of data to the SCM subsystem subsequent to the writing of the plurality of data to the at least one volatile memory device in the NVDIMM-N subsystem and, in response, update the cache tracking database; and
receive a shutdown signal and, in response, copy the cache tracking database to the at least one volatile memory device in the NVDIMM-N subsystem, wherein the NVDIMM-N subsystem is configured to copy at least some of the plurality of data and the cache tracking database from the at least one volatile memory device in the NVDIMM-N subsystem to the at least one non-volatile memory device in the NVDIMM-N subsystem prior to a shutdown associated with the shutdown signal.
2. The system of claim 1 , wherein the memory controller is configured to:
erase the first subset of the plurality of data from the at least one volatile memory device in the NVDIMM-N subsystem in response to writing the subset of the plurality of data to the SCM subsystem, wherein the erasing of the first subsystem of the plurality of data from the at least one volatile memory device in the NVDIMM-N subsystem provides a second subset of the plurality of data on the at least one volatile memory device in the NVDIMM-N subsystem.
3. The system of claim 2 , wherein the at least some of the plurality of data that is copied by the NVDIMM-N subsystem from the at least one volatile memory device in the NVDIMM-N subsystem to the at least one non-volatile memory device in the NVDIMM-N subsystem prior to the shutdown is the second subset of the plurality of data.
4. The system of claim 2 , wherein the cache tracking database details storage locations and statuses of the first subset of the plurality of data on the SCM subsystem and the second subset of the plurality of data on the at least one volatile memory subsystem in the NVDIMM-N subsystem.
5. The system of claim 1 , wherein the at least one volatile memory device in the NVDIMM-N subsystem includes at least one Dynamic Random Access Memory (DRAM) device, and the at least one non-volatile memory device in the NVDIMM-N subsystem includes at least one flash memory device.
6. The system of claim 1 , wherein the NVDIMM-N subsystem is configured to:
receive a restore signal subsequent to the shutdown and, in response, copy the at least some of the plurality of data and the cache tracking database from the at least one non-volatile memory device in the NVDIMM-N subsystem to the at least one volatile memory device in the NVDIMM-N subsystem, wherein the memory controller is configured to retrieve the cache tracking database from the at least one volatile memory device in the NVDIMM-N subsystem and copy the at least some of the plurality of data from the at least one volatile memory device in the NVDIMM-N subsystem to the SCM subsystem.
7. The system of claim 6 , further comprising:
a Basic Input/Output System (BIOS) that is configured to determine that the memory controller has copied the at least some of the plurality of data from the at least one volatile memory device in the NVDIMM-N subsystem to the SCM subsystem and, in response, erase the at least some of the plurality of data from the at least one volatile memory device in the NVDIMM-N subsystem.
8. An Information Handling System (IHS), comprising:
a chassis;
a memory system that is located in the chassis and that includes:
a Storage Class Memory (SCM) subsystem; and
a Non-Volatile Dual Inline Memory Module (NVDIMM-N) subsystem including at least one volatile memory device and at least one non-volatile memory device;
a processing system that is coupled to the memory system and that is configured to:
write a plurality of data to the at least one volatile memory device in the NVDIMM-N subsystem and, in response, update a cache tracking database;
write a first subset of the plurality of data to the SCM subsystem subsequent to the writing of the plurality of data to the at least one volatile memory device in the NVDIMM-N subsystem and, in response, update the cache tracking database; and
receive a shutdown signal and, in response, copy the cache tracking database to the at least one volatile memory device in the NVDIMM-N subsystem, wherein the NVDIMM-N subsystem is configured to copy at least some of the plurality of data and the cache tracking database from the at least one volatile memory device in the NVDIMM-N subsystem to the at least one non-volatile memory device in the NVDIMM-N subsystem prior to a shutdown associated with the shutdown signal.
9. The IHS of claim 8 , wherein the processing system is configured to:
erase the first subset of the plurality of data from the at least one volatile memory device in the NVDIMM-N subsystem in response to writing the subset of the plurality of data to the SCM subsystem, wherein the erasing of the first subsystem of the plurality of data from the at least one volatile memory device in the NVDIMM-N subsystem provides a second subset of the plurality of data on the at least one volatile memory device in the NVDIMM-N subsystem.
10. The IHS of claim 9 , wherein the at least some of the plurality of data that is copied by the NVDIMM-N subsystem from the at least one volatile memory device in the NVDIMM-N subsystem to the at least one non-volatile memory device in the NVDIMM-N subsystem prior to the shutdown is the second subset of the plurality of data.
11. The IHS of claim 9 , wherein the cache tracking database details storage locations and statuses of the first subset of the plurality of data on the SCM subsystem and the second subset of the plurality of data on the at least one volatile memory subsystem in the NVDIMM-N subsystem.
12. The IHS of claim 8 , wherein the NVDIMM-N subsystem is configured to:
receive a restore signal subsequent to the shutdown and, in response, copy the at least some of the plurality of data and the cache tracking database from the at least one non-volatile memory device in the NVDIMM-N subsystem to the at least one volatile memory device in the NVDIMM-N subsystem, wherein the processing system is configured to retrieve the cache tracking database from the at least one volatile memory device in the NVDIMM-N subsystem and copy the at least some of the plurality of data from the at least one volatile memory device in the NVDIMM-N subsystem to the SCM subsystem.
13. The IHS of claim 12 , further comprising:
a Basic Input/Output System (BIOS) that is configured to determine that the processing system has copied the at least some of the plurality of data from the at least one volatile memory device in the NVDIMM-N subsystem to the SCM subsystem and, in response, erase the at least some of the plurality of data from the at least one volatile memory device in the NVDIMM-N subsystem.
14. A method for providing a Storage Class Memory (SCM) memory mode Non-Volatile Dual Inline Memory Module (NVDIMM-N) cache, comprising:
writing, by a memory controller to at least one volatile memory device in an Non-Volatile Dual Inline Memory Module (NVDIMM-N) subsystem, a plurality of data and, in response, updating a cache tracking database;
writing, by the memory controller to an Storage Class Memory (SCM) subsystem subsequent to the writing of the plurality of data to the at least one volatile memory device in the NVDIMM-N subsystem, a first subset of the plurality of data and, in response, updating the cache tracking database;
receiving, by the memory controller, a shutdown signal and, in response, copying the cache tracking database to the at least one volatile memory device in the NVDIMM-N subsystem; and
copying, by the NVDIMM-N subsystem, at least some of the plurality of data and the cache tracking database from the at least one volatile memory device in the NVDIMM-N subsystem to the at least one non-volatile memory device in the NVDIMM-N subsystem prior to a shutdown associated with the shutdown signal.
15. The method of claim 14 , further comprising:
erasing, by the memory controller, the first subset of the plurality of data from the at least one volatile memory device in the NVDIMM-N subsystem in response to writing the subset of the plurality of data to the SCM subsystem, wherein the erasing of the first subsystem of the plurality of data from the at least one volatile memory device in the NVDIMM-N subsystem provides a second subset of the plurality of data on the at least one volatile memory device in the NVDIMM-N subsystem.
16. The method of claim 15 , wherein the at least some of the plurality of data that is copied by the NVDIMM-N subsystem from the at least one volatile memory device in the NVDIMM-N subsystem to the at least one non-volatile memory device in the NVDIMM-N subsystem prior to the shutdown is the second subset of the plurality of data.
17. The method of claim 15 , wherein the cache tracking database details storage locations and statuses of the first subset of the plurality of data on the SCM subsystem and the second subset of the plurality of data on the at least one volatile memory subsystem in the NVDIMM-N subsystem.
18. The method of claim 14 , wherein the at least one volatile memory device in the NVDIMM-N subsystem includes at least one Dynamic Random Access Memory (DRAM) device, and the at least one non-volatile memory device in the NVDIMM-N subsystem includes at least one flash memory device.
19. The method of claim 14 , further comprising:
receiving, by the NVDIMM-N subsystem, a restore signal subsequent to the shutdown and, in response, copying the at least some of the plurality of data and the cache tracking database from the at least one non-volatile memory device in the NVDIMM-N subsystem to the at least one volatile memory device in the NVDIMM-N subsystem; and
retrieving, by the memory controller, the cache tracking database from the at least one volatile memory device in the NVDIMM-N subsystem and copying the at least some of the plurality of data from the at least one volatile memory device in the NVDIMM-N subsystem to the SCM subsystem.
20. The method of claim 19 , further comprising
determining, by a Basic Input/Output System (BIOS), that the memory controller has copied the at least some of the plurality of data from the at least one volatile memory device in the NVDIMM-N subsystem to the SCM subsystem and, in response, erasing the at least some of the plurality of data from the at least one volatile memory device in the NVDIMM-N subsystem.