PARITY DATA MANAGEMENT SYSTEM APPARATUS AND METHOD

• US 20090187786A1
• Filed: 01/17/2008
• Published: 07/23/2009
• Est. Priority Date: 01/17/2008
• Status: Active Grant

• Current Assignee: LinkedIn Corporation (Microsoft Corporation)
• Original Assignee: International Business Machines Corporation
• Inventors: Kubo, Robert Akira, Kahler, David Ray, Nielsen, Karl Allen, Jones, Michael John, Song, Cheng-Chung, Travis, William Henry
• Granted Patent: US 7,849,356 B2
• Time in Patent Office: Days
• US Class Current: 714/7
• CPC Class Codes: G06F 11/1076 Parity data used in redundant arrays of independent storages, e.g. in RAID systems
• CPC Class Codes: G06F 2211/1035 Keeping track, i.e. keeping track of data and parity changes

Abstract

An apparatus for parity data management receives a write command and write data from a computing device. The apparatus also builds a parity control structure corresponding to updating a redundant disk array with the write data and stores the parity control structure in a persistent memory buffer of the computing device. The apparatus also updates the redundant disk array with the write data in accordance with a parity control map and restores the RAID controller parity map from the parity control structure as part of a data recovery operation if updating the redundant disk array with the write data is interrupted by a RAID controller failure resulting in a loss of the RAID controller parity map. In certain embodiments, the parity control structure is a RAID controller parity map.

Claims

1. A method for parity data management, the method comprising:

receiving a write command comprising write data from a computing device;

building a parity control structure in accordance with updating at least one data stripe of a redundant disk array with the write data;

storing the parity control structure in a persistent memory buffer of the computing device;

updating update the at least one data stripe with the write data in accordance with a RAID controller parity map; and

restoring the RAID controller parity map from the parity control structure stored in the persistent memory buffer as part of a data recovery operation if updating the at least one data stripe is interrupted by a RAID controller failure resulting in a loss of the RAID controller parity map.

2. The method of claim 1, wherein the parity control structure comprises a copy of the RAID controller parity map.

3. The method of claim 2, wherein the parity control structure further comprises additional data configured to facilitate updating the at least one data stripe.

4. The method of claim 1, further comprising discarding the parity control structure from the persistent memory of the computing device once the at least one data stripe is updated with the write data.

5. The method of claim 1, further comprising communicating a data strip updated message to the computing device once each data strip corresponding to the write data is successfully updated with the write data.

6. The method of claim 1, further comprising communicating the parity control structure to a RAID controller configured to store the parity control structure in the persistent memory buffer of an additional computing device and restoring the RAID controller parity map from the additional computing device if restoration of the RAID controller parity map from the computing device is unsuccessful.

7. A signal bearing medium tangibly embodying a program of machine-readable instructions executable by a digital processing apparatus to perform operations for parity data management, the operations comprising:

receiving a write command comprising write data from a computing device;

building a parity control structure in accordance with updating at least one data stripe of a redundant disk array with the write data;

storing the parity control structure in a persistent memory buffer of the computing device;

updating update the at least one data stripe with the write data in accordance with a RAID controller parity map; and

restoring the RAID controller parity map from the parity control structure stored in the persistent memory buffer as part of a data recovery operation if updating the at least one data stripe is interrupted by a RAID controller failure resulting in a loss of the RAID controller parity map.

8. The signal bearing medium of claim 7, wherein the parity control structure comprises a copy of the RAID controller parity map.

9. The signal bearing medium of claim 8, wherein the parity control structure further comprises additional data configured to facilitate updating the at least one data stripe.

10. The signal bearing medium of claim 7, further comprising discarding the parity control structure from the persistent memory of the computing device once the at least one data stripe is updated with the write data.

11. The signal bearing medium of claim 7, further comprising communicating a data strip updated message to the computing device once each data strip corresponding to the write data is successfully updated with the write data.

12. The signal bearing medium of claim 7, further comprising communicating the parity control structure to a RAID controller configured to store the parity control structure in the persistent memory buffer of an additional computing device and restoring the RAID controller parity map from the additional computing device if restoration of the RAID controller parity map from the computing device is unsuccessful.

13. A parity data management system, the system comprising:

a first computing device configured to communicate a write command comprising write data to a first RAID controller;

the first RAID controller configure to receive the write command and build a parity control structure in accordance with updating at least one data stripe of a redundant disk array with the write data;

the first RAID controller further configured to store the parity control structure in a persistent memory buffer of the first computing device;

the first RAID controller further configured to update the at least one data stripe with the write data in accordance with a RAID controller parity map; and

the first RAID controller further configured to restore the RAID controller parity map from the parity control structure stored in the persistent memory buffer of the first computing device as part of a data recovery operation if updating the at least one data stripe is interrupted by a RAID controller failure resulting in a loss of the RAID controller parity map.

14. The system of claim 13, wherein first RAID controller is further configured to discard the parity control structure from the persistent memory of the computing device once the at least one data stripe is updated with the write data.

15. The system of claim 13, wherein the first RAID controller is further configured to communicate a data strip updated message to the computing device once each data strip corresponding to the write data is successfully updated with the write data.

16. The system of claim 13, wherein the first RAID controller is further configured to communicate the parity control structure to a second RAID controller configured to communicate the parity control structure to a second computing device.

17. The system of claim 16, wherein the first RAID controller is further configured to restore the RAID controller parity map from the additional computing device if restoration of the RAID controller parity map from the computing device is unsuccessful.

18. The system of claim 16, wherein the second RAID controller is configured to restore the RAID controller parity map from the parity control structure stored in the persistent memory buffer of the first computing device as part of a data recovery operation if updating the at least one data stripe is interrupted by a RAID controller failure resulting in a loss of the RAID controller parity map.

19. A parity data management system, the system comprising:

a first computing device configured to communicate a write command comprising write data to a first RAID controller;

the first RAID controller configured to build a parity control structure in accordance with updating at least one data stripe of a redundant disk array with the write data;

the first RAID controller further configured to store the parity control structure in a persistent memory buffer of the first computing device;

the first RAID controller further configured to communicate the parity control structure to a second RAID controller;

the second RAID controller configured to store the parity control structure in a persistent memory buffer of a second computing device;

the first RAID controller further configured to update the at least one data stripe with the write data in accordance with a RAID controller parity map; and

the first RAID controller further configured to restore the RAID controller parity map from the parity control structure stored in the persistent memory buffer of the first computing device as part of a data recovery operation if updating the at least one data stripe is interrupted by a RAID controller failure resulting in a loss of the RAID controller parity map;

the first RAID controller further configured to restore the RAID controller parity map from the parity control structure stored in the persistent memory buffer of the second computing device as part of a data recovery operation if restoration of the RAID controller parity map from the first computing device is unsuccessful.