I/O operations for a storage array

• US 7,925,829 B1
• Filed: 03/29/2007
• Issued: 04/12/2011
• Est. Priority Date: 03/29/2007
• Status: Active Grant

• Current Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Original Assignee: EMC Corporation (Dell Technologies Inc.)
• Inventors: Veprinsky, Alexandr, Michael, Ofer E., Scharland, Michael J.
• Primary Examiner(s): Gu; Shawn X
• Application Number:
  US11/729,707
• Time in Patent Office: 1,475 Days
• Field of Search: None
• US Class Current: 711/114
• CPC Class Codes: G06F 11/2089 Redundant storage control functionality
• CPC Class Codes: G06F 3/0605 by facilitating the interaction with a user or administrator
• CPC Class Codes: G06F 3/0629 Configuration or reconfiguration of storage systems
• CPC Class Codes: G06F 3/0659 Command handling arrangements, e.g. command buffers, queues, command scheduling
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]

Abstract

Handling I/O operations for a storage array includes distributing metadata among separate memories of a plurality of directors of the storage array, where the metadata correlates logical device data with physical device data. A first one of the directors receives an I/O operation for a particular logical device. Handling I/O operations may also include determining which of the plurality of directors contains metadata corresponding to the particular logical device, and, in response to the metadata being on a different one of the directors, the first director providing a request to the different one of the directors. The directors may be interconnected by an interconnect fabric. The first one of the directors may provide a request to the second one of the directors via the interconnect fabric. Determining which of the plurality of directors contains metadata correspond to the particular logical device may include using a lookup table.

Claims

1. A method of handling I/O operations for a storage array, comprising:

distributing metadata among separate memories of a plurality of directors of the storage array, wherein the metadata correlates logical device data with physical device data, and wherein the separate memories include different portions of a global memory distributed among the plurality of directors, each of the different portions of the global memory being accessible by each of the plurality of directors;

a first one of the directors receiving an I/O operation for a particular logical device;

determining which of the plurality of directors includes the portion of the global memory that contains metadata corresponding to the particular logical device; and

in response to the corresponding metadata being on the portion of the global memory of a different one of the directors, the first director providing a request to the different one of the directors, the request corresponding to the I/O operation for the particular logical device, wherein, although the first director is capable of accessing the portion of the global memory of the different one of the directors and servicing the I/O operation via a non-native global memory access, the first director provides the request to the different one of the directors having the portion of the global memory that contains the corresponding metadata for servicing the I/O operation via a native global memory access.

2. A method, according to claim 1, and wherein the directors are interconnected by a interconnect fabric.

3. A method, according to claim 2, wherein the first one of the directors provides a request to the second one of the directors via the interconnect fabric.

4. A method, according to claim 1, wherein determining which of the plurality of directors contains metadata corresponding to the particular logical device includes using a lookup table.

5. A method, according to claim 1, wherein the physical device data is provided by at least one disk drive coupled to at least one of the directors.

6. A method, according to claim 1, further comprising:

determining a particular physical device that corresponds to the particular logical device;

determining which of the plurality of directors corresponds to the particular physical device; and

in response to the physical device corresponding to a different one of the directors, the first director providing a request to the different one of the directors.

7. A method, according to claim 1, wherein the metadata includes device tables and cache slots.

8. A method of handling I/O operations for a storage array, comprising:

distributing metadata among separate memories of a plurality of directors of the storage array, wherein the metadata correlates logical device data with physical device data, and wherein the separate memories include different portions of a global memory distributed among the plurality of directors, each of the different portions of the global memory being accessible by each of the plurality of directors;

a first one of the directors receiving an I/O operation for a particular logical device;

determining a particular physical device that corresponds to the particular logical device;

determining which of the plurality of directors includes the portion of the global memory that contains metadata that corresponds to the particular physical device; and

in response to the corresponding metadata for the physical device being on the portion of the global memory of a different one of the directors, the first director providing a request to the different one of the directors, the request corresponding to the I/O operation for the particular logical device, wherein, although the first director is capable of accessing the portion of the global memory of the different one of the directors and servicing the I/O operation via a non-native global memory access, the first director provides the request to the different one of the directors having the portion of the global memory that contains the corresponding metadata for servicing the I/O operation via a native global memory access.

9. A method, according to claim 8, and wherein the directors are interconnected by a interconnect fabric.

10. A method, according to claim 9, wherein the first one of the directors provides a request to the second one of the directors via the interconnect fabric.

11. A method, according to claim 8, wherein determining which of the plurality of directors includes the portion of the global memory that includes metadata that corresponds to the particular physical device includes using a lookup table.

12. A method, according to claim 8, wherein the physical device data is provided by at least one disk drive coupled to at least one of the directors.

13. A method, according to claim 8, wherein the metadata includes device tables and cache slots.

14. A storage array, comprising:

a plurality of directors, each having at least one processor thereon;

a global memory distributed among the plurality of directors, wherein different portions of the global memory are provided on each of the directors, and wherein each of the different portions of the global memory is accessible by each of the plurality of directors;

an interconnect fabric coupled to each of the directors, wherein global memory accesses performed by one director to access memory of another director are through the interconnect fabric; and

metadata for logical devices, provided in the global memory, wherein the metadata contains information that correlates logical device data with physical device data and wherein, in response to an I/O operation for a particular logical device, a first director determines which of the plurality of directors includes the portion of the global memory that contains metadata corresponding to the particular logical device and, in response to the metadata being on the portion of the global memory of a different one of the directors, the first director provides a request to the different one of the directors, the request corresponding to the I/O operation for the particular logical device, wherein, although the first director is capable of accessing the portion of the global memory of the different one of the directors and servicing the I/O operation via a non-native global memory access, the first director provides the request to the different one of the directors having the portion of the global memory that contains the corresponding metadata for servicing the I/O operation via a native global memory access.

15. A storage array, according to claim 14, wherein the physical device data is provided by at least one disk drive coupled to at least one of the directors.

16. A storage array, according to claim 14, further comprising:

a local memory, provided on each of the directors, wherein the local memory is accessed exclusively by the at least one processor of a corresponding one of the directors.

17. A storage array, according to claim 14, wherein the metadata includes device tables and cache slots.

18. A storage array, according to claim 14, wherein the interconnect fabric is implemented using an Internet Protocol (IP) network.

19. A storage array, according to claim 14, wherein each of the directors includes a interconnect fabric interface and wherein the interconnect fabric interface includes Direct Memory Access (DMA) hardware.