Hot replacement of storage device in serial array of storage devices

• US 6,370,604 B1
• Filed: 05/07/1999
• Issued: 04/09/2002
• Est. Priority Date: 05/07/1999
• Status: Active Grant

• Current Assignee: Intel Network Systems, Inc. (Intel Corporation)
• Original Assignee: Intel Corporation
• Inventors: Sreekanti, Kumar
• Primary Examiner(s): Shin, Christopher B.
• Application Number:
  US09/307,301
• Time in Patent Office: 1,068 Days
• Field of Search: 710/1-11, 710/15-19, 710/36-45, 710/52-56, 710/100-103, 710/107-114, 710/129-131, 711/111-114, 709/224, 714/5-6
• US Class Current: 710/302
• CPC Class Codes: G06F 11/2094 Redundant storage or storage space G06F11/2056 takes precedence
• CPC Class Codes: G06F 13/4081 Live connection to bus, e.g. hot-plugging current or voltage limitation during live insertion H02H9/004
• CPC Class Codes: G06F 3/0601 Interfaces specially adapted for storage systems
• CPC Class Codes: G06F 3/0673 Single storage device

Abstract

Hot replacement of a storage device in a serial array of storage devices. The apparatus and the process of the invention allow one device to be removed from the array, without causing critical error to be delivered to the host computer and, in turn, all of the delays and problems associated with the delivery of such an error signal. The invention includes a buffer to buffer data requests from the host computer while the replacement process is ongoing. After the drive is replaced, the requests stored in the buffer are performed.

Claims

1. A hot replacement process for replacing a to-be-replaced data storage device in an array of data storage devices serially connected to one another while the array continues to receive requests for the storage or retrieval of data from a host computer to which the array is connected, comprising:

a) buffering the requests while the to-be-replaced storage device is being replaced;

b) deferring the processing of the requests while they are being buffered;

c) replacing the to-be-replaced storage device with another storage device while the requests are being buffered; and

d) processing the buffered requests after the to-be-replaced storage device has been replaced by the other storage device.

2. The hot replacement process of claim 1 further comprising:

a) signaling that the to-be-replaced storage device is about to be replaced;

b) completing any request that is in the process of being fulfilled at the time of said signaling; and

c) after any request that was in the process of being fulfilled at the time of said signaling has been completed;

i) initiating

a) said buffering of the requests; and

b) said deferring of the processing of the requests; and

ii) signaling that it is safe to remove the to-be-replaced storage device from the array for replacement.

3. The hot replacement process of claim 1 wherein all of the requests that are generated by the host computer while the to-be-replaced storage device is being replaced are buffered and deferred.

4. The hot replacement process of claim 1 wherein a software driver is used to effectuate a portion of said process.

5. The hot replacement process of claim 4 wherein the software driver is loaded in the host computer.

6. The hot replacement process of claim 4 wherein the software driver is loaded in the storage array.

7. The hot replacement process of claim 1 wherein each of the storage devices is a hard disk drive.

8. A data storage and retrieval system, comprising:

a) an array of data storage devices serially connected to one another for receiving requests for the storage or retrieval of data from a computer;

b) a buffer for buffering the requests from the computer; and

c) a processor associated with said buffer and said array for;

i) causing said buffer to buffer the requests from the computer while one of said storage devices is being replaced;

ii) causing the processing of the requests to be deferred while they are being buffered; and

iii) causing the buffered requests to be processed after the storage device has been replaced.

9. The system of claim 8 further including a replace device notifier for notifying when it is safe to remove the storage device from the array and wherein said processor further:

a) receives a signal that the storage device is about to be replaced;

b) causes any request that is in the process of being fulfilled at the time of the signaling to be completed; and

c) after any request that was in the process of being fulfilled at the time of the signaling to be completed;

i) initiates

a) the buffering of the requests by said buffer; and

b) the deferring of the processing of the requests; and

ii) causes the notifier to notify that it is safe to remove the storage device from the array.

10. The system of claim 8 wherein said processor also causes all of the requests that are received from the computer while the storage device is being replaced to be buffered and deferred.

11. The system of claim 8 wherein said processor includes a software driver.

12. The system of claim 11 wherein said software driver is configured to be loaded in the computer.

13. The system of claim 11 wherein said software driver is configured to be loaded in said array.

14. A data storage device containing a software driver configured after installation to cause:

a) the buffering of requests from a computer to read or write data to an array of data storage devices serially connected to one another while one of the storage devices is being replaced;

b) the processing of the requests to be defer red while they are being buffered; and

c) the processing of the buffered requests after the storage device has been replaced.

15. A hot replacement process for replacing a to-be-replaced component in a data storage device while the device continues to receive requests for the storage or retrieval of data from a host computer to which the device is connected, comprising:

a) buffering the requests while the to-be-replaced component is being replaced;

b) deferring the processing of the requests while they are being buffered;

c) replacing the to-be-replaced component with another component while the requests are being buffered; and

d) processing the buffered requests after the to-be-replaced component has been replaced.

16. A data storage and retrieval system comprising:

a) a data storage device for receiving requests for the storage or retrieval of data from a computer, said device including a component necessary for the operation of said device;

b) a buffer for buffering the requests from the computer; and

c) a processor associated with said buffer and said device for;

i) causing said buffer to buffer the requests from the computer while said component is being replaced;

ii) causing the processing of requests to be deferred while they are being buffered; and

iii) causing the buffered requests to be processed after said component has been replaced.