Storage system with local and remote storage devices which are managed by the local storage device

• US 8,959,285 B2
• Filed: 04/10/2008
• Issued: 02/17/2015
• Est. Priority Date: 01/02/2008
• Status: Active Grant

• Current Assignee: Jpmorgan Chase Bank NA As The Agent
• Original Assignee: Sandisk Technologies Incorporated (Western Digital Corporation)
• Inventors: Nochimowski, Alain, Marcu, Alon, Rave, Micha, Pomerantz, Itzhak
• Primary Examiner(s): Shah, Sanjiv
• Assistant Examiner(s): Ayash, Marwan
• Application Number:
  US12/101,065
• Publication Number:
  US 20090172276A1
• Time in Patent Office: 2,504 Days
• Field of Search: None
• US Class Current: 711/114
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 3/0604 Improving or facilitating administration, e.g. storage management
• CPC Class Codes: G06F 3/0607 by facilitating the process of upgrading existing storage systems, e.g. for improving compatibility between host and storage device
• CPC Class Codes: G06F 3/0655 Vertical data movement, i.e. input-output transfer; data movement between one or more hosts and one or more storage devices
• CPC Class Codes: G06F 3/0664 at device level, e.g. emulation of a storage device or system
• CPC Class Codes: G06F 3/0679 Non-volatile semiconductor memory device, e.g. flash memory, one time programmable memory [OTP]

Abstract

A method of servicing a command sent from a host device file system (HDFS) within a host device (HD) by a local storage device (LSD) in communication with the HD is described. The method includes receiving a first command at the LSD instructing the LSD to execute an operation on associated logical addresses. If the first command is associated with at least a first set of logical addresses, the method includes servicing the first command by the LSD at least by way of sending a second command to a device (RD) external to the LSD that instructs the RD to execute an operation on memory locations within the RD. If the first command is not associated with the first set of logical addresses, the method includes servicing the first command by the LSD only by way of operations executed by the LSD on memory locations within the LSD.

Claims

1. A method of servicing a management command sent from a host device file system (HDFS) within a host device (HD), the method comprising:

in a local storage device (LSD) in communication with the HD over a HD/LSD interface configured to connect with the host device such that the LSD is connected exclusively with the HD;

receiving a first management command from the HD over a first communication path over the HD/LSD interface, the first management command instructing the LSD to execute an operation on associated logical addresses;

when the first management command is associated with at least a first set of logical addresses, sending from the LSD, over a second communication path established over the HD/LSD interface, a second management command to a remote device (RD) external to the LSD and the HD that instructs the RD to execute an operation on memory locations within the RD, the sending of the second management command to the RD and the execution of the operation associated with the first management command on the memory locations within the RD being invisible to the HDFS; and

when the first management command is not associated with at least the first set of logical addresses, servicing the first management command only by way of operations executed on memory locations within the LSD;

wherein the LSD manages the storage of data files such that commonly accessed data files are stored at the LSD and data files that are not commonly accessed are stored at the RD.

2. The method as recited in claim 1, wherein the LSD presents a perceived storage capacity (PSC) to the HDFS, the PSC comprising an amount of storage capacity at least equal to a sum of the RD storage capacity and the LSD storage capacity.

3. The method as recited in claim 1, further comprising:

if the first management command is associated with at least the first set of logical addresses,

prompting the HD by the LSD to establish the second communication path between the LSD and the RD via the HD, wherein once the communication path is established, no further intervention by the HD is required except to maintain the communication path; and

logically interacting with the RD over the second communication path, wherein the logical interacting and the prompting are each invisible to the HDFS.

4. The method as recited in claim 3, wherein the logically interacting comprises:

sending at least the second management command from the LSD to the RD;

receiving an RD response from the RD in response to the second management command; and

sending at least an LSD response from the LSD to the HDFS.

5. The method as recited in claim 4, wherein when the first management command is a memory WRITE command, then the second management command is a WRITE command that includes data to be stored in the RD and wherein the RD response includes a WRITE acknowledgment signal.

6. The method as recited in claim 5, wherein the data to be stored in the RD is cached in the LSD prior to being forwarded to the RD.

7. The method as recited in claim 4, wherein when the first management command is a memory READ command, then the second management command is a READ command and wherein the RD response includes data to be sent to the HD via the LSD response.

8. The method as recited in claim 1, wherein the LSD further comprises:

an LSD memory controller including a memory manager arranged to manage at least a mass storage region of the LSD memory array based at least upon management commands received from the HDFS.

9. The method as recited in claim 8, wherein the mass storage region of the LSD memory array includes a file allocation table (FAT) that includes at least one FAT entry having at least a data file identifier entry corresponding to a data file and including logical addresses associated with the data file.

10. The method as recited in claim 9, further comprising mapping, with a mapping module in the LSD, the logical sector addresses associated with the file to real sectors or virtual sectors, wherein real sectors comprise physical sectors in the LSD and virtual sectors comprise physical sectors within the RD.

11. The method as recited in claim 10, further comprising dynamically modifying the allocation of real and virtual sectors to content stored within the LSD memory array and the RD transparently to the HDFS.

12. The method as recited in claim 11, wherein most commonly accessed files are stored in real sectors.

25. The method of claim 1, wherein the LSD is embedded in the HD.

26. The method of claim 1, wherein the LSD comprises three-dimensional memory.

13. A local storage device (LSD) comprising:

a host device/local storage (HD/LSD) interface configured for connecting with a host device (HD) having at least a host device file system (HDFS), wherein the HD/LSD connects the LSD to the HD such that the LSD is connected exclusively with the HD; and

a memory array, the memory array being logically arranged to include at least one mass storage region externally managed by the HDFS; and

a LSD controller in communication with the HD/LSD interface and the memory, the LSD controller configured to;

receive a management command by way of a first communication path over the HD/LSD interface, the management command instructing the LSD to execute an operation on associated logical addresses;

when the LSD controller determines that a first management command received from the HDFS is associated with at least a first set of logical addresses, send a second management command from the LSD to a remote device (RD) external to the LSD and the HD by way of a second communication path over the HD/LSD interface that instructs the RD to execute an operation on memory locations within the RD, the sending of the second management command to the RD and the execution of the operation associated with the first management command on the memory locations within the RD being invisible to the HDFS; and

when the LSD controller determines that the first management command received from the HDFS is associated with at least a second set of logical addresses, execute the first management command on memory locations within the LSD mass storage region;

wherein the LSD manages the storage of data files such that commonly accessed data files are stored at the LSD and data files that are not commonly accessed are stored at the RD.

14. The LSD as recited in claim 13, wherein the LSD comprises a perceived storage capacity (PSC), the PSC being an amount of storage capacity of the LSD perceived by the HDFS, and wherein the PSC is at least equal to sum of RD storage capacity and LSD storage capacity.

15. The LSD as recited in claim 13, wherein if the first management command is associated with at least the first set of logical addresses, the controller is configured to, with an LSD agent within the LSD controller, prompt the HD to establish the second communication path between the LSD and the RD via the HD, wherein once the second communication path is established the LSD and the RD logically interact over the second communication path, wherein the logical interaction and the prompting are each invisible to the HDFS.

16. The LSD as recited in claim 15, wherein, to logically interact, controller is configured to:

send at least the second management command from the LSD to the RD;

receive an RD response from the RD in response to sending the second management command; and

send at least an LSD response from the LSD to the HDFS.

17. The LSD as recited in claim 16, wherein when the first management command is a memory WRITE command, then the second management command is a WRITE command that includes data to be stored in the RD and wherein the RD response includes a WRITE acknowledgment signal.

18. The LSD as recited in claim 17, wherein the controller is configured to cache data to be stored in the RD in the LSD prior to forwarding the data to the RD.

19. The LSD as recited in claim 16, wherein when the first management command is a memory READ command, then the second management command is a READ command and wherein the RD response includes data to be sent to the HD via the LSD response.

20. The LSD as recited in claim 13, wherein the LSD memory array includes a file allocation table (FAT) that includes at least one FAT entry having at least a data file identifier entry corresponding to a data file and including logical addresses associated with the data file.

21. The LSD as recited in claim 20, where the LSD further comprises a mapping module configured to map logical sector addresses associated with the file to real sectors or virtual sectors, wherein real sectors comprise physical sectors in a memory array of the LSD and virtual sectors comprise physical sectors within the RD.

22. The LSD as recited in claim 21, wherein the mapping module is configured to dynamically modify the allocation of real and virtual sectors to content stored within the LSD memory array and the RD transparently to the HDFS.

23. The LSD as recited in claim 22, wherein the most commonly accessed files are stored in real sectors.

24. The LSD of claim 13, wherein the LSD is embedded in the HD.

27. The LSD of claim 13, wherein the memory array comprises three-dimensional memory.