Techniques for managing data within a data storage system utilizing a flash-based memory vault

• US 20070220227A1
• Filed: 03/17/2006
• Published: 09/20/2007
• Est. Priority Date: 03/17/2006
• Status: Active Grant

• Current Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Original Assignee: EMC Corporation (Dell Technologies Inc.)
• Inventors: Long, Matthew
• Granted Patent: US 7,421,552 B2
• Time in Patent Office: Days
• US Class Current: 711/165
• CPC Class Codes: G06F 11/1441 Resetting or repowering

Abstract

A technique for managing data within a data storage system involves performing data storage operations on behalf of a set of hosts (i.e., one or more hosts) using a volatile-memory storage cache and a set of magnetic disk drives while the data storage system is being powered by a primary power source (e.g., a main power feed). The technique further involves receiving a power failure signal (e.g., from a sensor) indicating that the data storage system is now being powered by a backup power source rather than by the primary power source (e.g., due to a loss of the main power feed, due to a failure of a power converter, etc.), and moving data from the volatile-memory storage cache of the data storage system to a flash-based memory vault of the data storage system in response to the power failure signal.

Claims

1. A data storage system, comprising:

a volatile-memory storage cache;

a flash-based memory vault; and

a controller coupled to the volatile-memory storage cache and the flash-based memory vault, the controller being configured to;

while the controller is being powered by a primary power source, performing data storage operations on behalf of a set of hosts using the volatile-memory storage cache and a set of magnetic disk drives,

receiving a power failure signal indicating that the controller is now being powered by a backup power source rather than by the primary power source, and

moving data from the volatile-memory storage cache to a flash-based memory vault in response to the power failure signal.

2. A data storage system as in claim 1 wherein the controller includes processing circuitry which is configured to consume power (i) at a first power consumption rate when running at a first clock speed and (ii) at a second power consumption rate when running at a second clock speed, the second power consumption rate being lower than the first power consumption rate, and the second clock speed being slower than the first clock speed;

wherein the controller, when performing the data storage operations, is configured to run the processing circuitry at the first clock speed; and

wherein the controller, when moving the data from the volatile-memory storage cache to the flash-based memory vault, is configured to run the processing circuitry at the second clock speed to conserve power from the backup power source while the processing circuitry moves the data from the volatile-memory storage cache to the flash-based memory vault.

3. A data storage system as in claim 2 wherein the controller, when running the processing circuitry at the first clock speed, is configured to operate a microprocessor of the processing circuitry within a first power range which is between 50 Watts and 100 Watts;

and

wherein running the processing circuitry at the second clock speed includes operating the microprocessor of the processing circuitry within a second power range which is less than 30 Watts.

4. A data storage system as in claim 1 wherein (i) the volatile-memory storage cache, (ii) the flash-based memory vault and (iii) a controller configured to perform data storage operations reside within a processing core of the data storage system;

and wherein the data storage system further comprises;

isolation circuitry configured to electrically isolate the processing core from other portions of the data storage system in response to the power failure signal to enable the controller to move the data from the volatile-memory storage cache to the flash-based memory vault without interference from the other portions of the data storage system.

5. A data storage system as in claim 1 wherein the flash-based memory vault is configured as a removable module to enable a user to

disconnect the flash-based memory vault from the data storage system,

connect the flash-based memory vault to a new data storage system, and

restore the data from the flash-based memory vault to a new volatile-memory storage cache of the new data storage system to continue to perform data storage operations on behalf of the set of hosts.

6. A data storage system as in claim 1 wherein the controller is further configured to:

receive a power normal signal; and

restore the data from the flash-based memory vault to the volatile-memory storage cache in response to the power normal signal.

7. A data storage system as in claim 1 wherein the data storage system includes:

a first storage processor having a first storage cache and a first memory vault, and

a second storage processor having a second storage cache and a second memory vault, the first and second storage caches being configured to mirror data, the first and second storage caches forming the volatile-memory storage cache of the data storage system, the first and second memory vaults forming the flash-based memory vault; and

wherein the controller, when moving the data from the volatile-memory storage cache to the flash-based memory vault, is configured to;

store contents of the first storage cache to the first memory vault, and

store contents of the second storage cache to the second memory vault.

8. A data storage system as in claim 7 wherein the controller is further configured to:

receive a power normal signal; and

restore the first and second storage caches from the first and second memory vaults which form the flash-based memory vault in response to the power normal signal, the first and second storage caches mirroring each other once the first and second storage caches have been restored.

9. A data storage system as in claim 8 wherein the controller, when restoring the first and second storage caches, is configured to:

transfer the contents of the first storage cache stored in the first memory vault back to the first storage cache, and

copy the contents transferred back to the first storage cache from the first storage cache to the second storage cache.

10. A data storage system as in claim 8 wherein the controller, when restoring the first and second storage caches, is configured to:

transfer a top half of the contents of the first storage cache stored in the first memory vault back to the first storage cache,

transfer a bottom half of the contents of the second storage cache stored in the second memory vault back to the second storage cache,

copy the bottom half of the contents transferred back to the second storage cache from the second storage cache to the first storage cache, and

copy the top half of the contents transferred back to the first storage cache from the first storage cache to the second storage cache.

11. A data storage system as in claim 8 wherein the controller, when restoring the first and second storage caches, is configured to:

transfer the contents of the first storage cache stored in the first memory vault back to the first storage cache, and

transfer the contents of the second storage cache stored in the second memory vault back to the second storage cache.

12. A method for managing data within a data storage system, the method comprising:

while the data storage system is being powered by a primary power source, performing data storage operations on behalf of a set of hosts using a volatile-memory storage cache and a set of magnetic disk drives;

receiving a power failure signal indicating that the data storage system is now being powered by a backup power source rather than by the primary power source; and

moving data from the volatile-memory storage cache of the data storage system to a flash-based memory vault of the data storage system in response to the power failure signal.

13. A method as in claim 12 wherein a controller which performs the data storage operations includes processing circuitry that is configured to consume power (i) at a first power consumption rate when running at a first clock speed and (ii) at a second power consumption rate when running at a second clock speed, the second power consumption rate being lower than the first power consumption rate, and the second clock speed being slower than the first clock speed;

wherein performing the data storage operations includes running the processing circuitry at the first clock speed; and

wherein moving the data from the volatile-memory storage cache to the flash-based memory vault includes running the processing circuitry at the second clock speed to conserve power from the backup power source while the processing circuitry moves the data from the volatile-memory storage cache to the flash-based memory vault.

14. A method as in claim 13 wherein running the processing circuitry at the first clock speed includes operating a microprocessor of the processing circuitry within a first power range which is between 50 Watts and 100 Watts;

and

wherein running the processing circuitry at the second clock speed includes operating the microprocessor of the processing circuitry within a second power range which is less than 30 Watts.

15. A method as in claim 12 wherein (i) the volatile-memory storage cache, (ii) the flash-based memory vault and (iii) a controller configured to perform data storage operations reside within a processing core of the data storage system;

and wherein the method further comprises;

electrically isolating the processing core from other portions of the data storage system in response to the power failure signal to enable the controller to move the data from the volatile-memory storage cache to the flash-based memory vault without interference from the other portions of the data storage system.

16. A method as in claim 12, further comprising:

disconnecting the flash-based memory vault from the data storage system;

connecting the flash-based memory vault to a new data storage system; and

restoring the data from the flash-based memory vault to a new volatile-memory storage cache of the new data storage system to continue to perform data storage operations on behalf of the set of hosts.

17. A method as in claim 12, further comprising:

receiving a power normal signal; and

restoring the data from the flash-based memory vault to the volatile-memory storage cache in response to the power normal signal.

18. A method as in claim 12 wherein the data storage system includes:

a first storage processor having a first storage cache and a first memory vault, and

a second storage processor having a second storage cache and a second memory vault, the first and second storage caches being configured to mirror data, the first and second storage caches forming the volatile-memory storage cache of the data storage system, the first and second memory vaults forming the flash-based memory vault; and

wherein moving the data from the volatile-memory storage cache to the flash-based memory vault includes;

storing contents of the first storage cache to the first memory vault, and

storing contents of the second storage cache to the second memory vault.

19. A method as in claim 18, further comprising:

receiving a power normal signal; and

restoring the first and second storage caches from the first and second memory vaults which form the flash-based memory vault in response to the power normal signal, the first and second storage caches mirroring each other once the first and second storage caches have been restored.

20. A method as in claim 19 wherein restoring the first and second storage caches includes:

transferring the contents of the first storage cache stored in the first memory vault back to the first storage cache; and

copying the contents transferred back to the first storage cache from the first storage cache to the second storage cache.

21. A method as in claim 19 wherein restoring the first and second storage caches includes:

transferring a top half of the contents of the first storage cache stored in the first memory vault back to the first storage cache;

transferring a bottom half of the contents of the second storage cache stored in the second memory vault back to the second storage cache;

copying the bottom half of the contents transferred back to the second storage cache from the second storage cache to the first storage cache; and

copying the top half of the contents transferred back to the first storage cache from the first storage cache to the second storage cache.

22. A method as in claim 19 wherein restoring the first and second storage caches includes:

transferring the contents of the first storage cache stored in the first memory vault back to the first storage cache; and

transferring the contents of the second storage cache stored in the second memory vault back to the second storage cache.

23. A data storage system, comprising:

a volatile-memory storage cache;

a flash-based memory vault; and

a controller coupled to the volatile-memory storage cache and the flash-based memory vault, the controller including;

means for performing data storage operations on behalf of a set of hosts using the volatile-memory storage cache and a set of magnetic disk drives while the controller is being powered by a primary power source,

means for receiving a power failure signal indicating that the controller is now being powered by a backup power source rather than by the primary power source, and

means for moving data from the volatile-memory storage cache to a flash-based memory vault in response to the power failure signal.