AGGREGATION OF WRITE TRAFFIC TO A DATA STORE

• US 20140237173A1
• Filed: 04/22/2014
• Published: 08/21/2014
• Est. Priority Date: 09/19/2008
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Cong, Shi, Brender, Scott, Mehra, Karan, Moss, Darren G., Tipton, William R., Verma, Surendra
• Granted Patent: US 9,361,183 B2
• Time in Patent Office: Days
• US Class Current: 711/104
• CPC Class Codes: G06F 11/1435 using file system or storage system metadata
• CPC Class Codes: G06F 11/1471 involving logging of persistent data for recovery
• CPC Class Codes: G06F 12/0638 Combination of memories, e.g. ROM and RAM such as to permit replacement or supplementing of words in one module by words in another module address formation of the next microinstruction G06F9/26; masking faults in memories by using spares or by reconfiguring G11C29/70
• CPC Class Codes: G06F 12/121 using replacement algorithms
• CPC Class Codes: G06F 2212/2022 Flash memory
• CPC Class Codes: G06F 2212/205 Hybrid memory, e.g. using both volatile and non-volatile memory
• CPC Class Codes: G06F 2212/221 Static RAM
• CPC Class Codes: G06F 2212/2228 Battery-backed RAM
• CPC Class Codes: G06F 3/0611 in relation to response time
• CPC Class Codes: G06F 3/0656 Data buffering arrangements
• CPC Class Codes: G06F 3/0673 Single storage device
• CPC Class Codes: G11C 7/1006 Data managing, e.g. manipulating data before writing or reading out, data bus switches or control circuits therefor

Abstract

A method and a processing device are provided for sequentially aggregating data to a write log included in a volume of a random-access medium. When data of a received write request is determined to be suitable for sequentially aggregating to a write log, the data may be written to the write log and a remapping tree, for mapping originally intended destinations on the random-access medium to one or more corresponding entries in the write log, may be maintained and updated. At time periods, a checkpoint may be written to the write log. The checkpoint may include information describing entries of the write log. One or more of the checkpoints may be used to recover the write log, at least partially, after a dirty shutdown. Entries of the write log may be drained to respective originally intended destinations upon an occurrence of one of a number of conditions.

Claims

1. A method performed on a computer, the method comprising:

receiving a request to write data to an intended destination on a random access medium;

redirecting the data to an entry in a write log, where the redirected data is sequentially aggregated in the write log as opposed to being written to the intended destination on the random access medium per the received request; and

mapping, in response to the redirecting completing successfully, the intended destination to the entry of the redirected data in the write log.

2. The method of claim 1 where the redirecting is in response to determining that the data is not part of a stream.

3. The method of claim 1 where the redirecting is in response to determining that a size of the data is less than a particular size.

4. The method of claim 1 where the redirecting comprises write operations to the write log, and where at least some of the write operations are completed out of order.

5. The method of claim 1 further comprising draining the entry in the write log to the intended destination on the random access medium.

6. The method of claim 5 where the draining is in response to determining that the computer is not operating on battery power.

7. The method of claim 5 where the draining is in response to determining that new entries in the write log are not permitted.

8. A system comprising a computer and instructions stored in a storage device, the computer and the instructions together configured for performing actions comprising:

receiving a request to write data to an intended destination on a random access medium;

redirecting the data to an entry in a write log, where the redirected data is sequentially aggregated in the write log as opposed to being written to the intended destination on the random access medium per the received request; and

mapping, in response to the redirecting completing successfully, the intended destination to the entry of the redirected data in the write log.

9. The method of claim 8 where the redirecting is in response to determining that the data is not part of a stream.

10. The method of claim 8 where the redirecting is in response to determining that a size of the data is less than a particular size.

11. The method of claim 8 where the redirecting comprises write operations to the write log, and where at least some of the write operations are completed out of order.

12. The method of claim 8 further comprising draining the entry in the write log to the intended destination on the random access medium.

13. The method of claim 12 where the draining is in response to determining that the computer is not operating on battery power.

14. The method of claim 12 where the draining is in response to determining that new entries in the write log are not permitted.

15. A system comprising a computer that includes instructions stored in a storage device of the computer, the computer and the instructions together configured for performing actions comprising:

receiving a request to write data to an intended destination on a random access medium;

redirecting the data to an entry in a write log, where the redirected data is sequentially aggregated in the write log as opposed to being written to the intended destination on the random access medium per the received request; and

mapping, in response to the redirecting completing successfully, the intended destination to the entry of the redirected data in the write log.

16. The system of claim 15 where the redirecting is in response to determining that the data is not part of a stream.

17. The system of claim 15 where the redirecting is in response to determining that a size of the data is less than a particular size.

18. The system of claim 15 where the redirecting comprises write operations to the write log, and where at least some of the write operations are completed out of order.

19. The system of claim 15 further comprising draining the entry in the write log to the intended destination on the random access medium.

20. The system of claim 19 where the draining is in response to determining that the computer is not operating on battery power, or where the draining is in response to determining that new entries in the write log are not permitted.