Apparatus and method for controlling storage device

• US 20060212603A1
• Filed: 03/02/2006
• Published: 09/21/2006
• Est. Priority Date: 03/17/2005
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Suzuki, Kazunari, Satoh, Masakazu
• Granted Patent: US 7,647,420 B2
• Time in Patent Office: Days
• US Class Current: 709/250
• CPC Class Codes: H04L 67/1097 for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS]
• CPC Class Codes: H04L 67/2876 Pairs of inter-processing entities at each side of the network, e.g. split proxies
• CPC Class Codes: H04L 67/5682 Policies or rules for updating, deleting or replacing the stored data
• CPC Class Codes: H04L 67/59 Providing operational support to end devices by off-loading in the network or by emulation, e.g. when they are unavailable

Abstract

A method and apparatus for controlling a transmission of data from a first storage device to a second storage device. The first storage device includes a recording unit for recording the data, a buffer for temporarily storing the data read from the recording unit, and a transmission unit for transmitting the data read from the buffer. It is determined that sufficient buffer space in the buffer is not available for the transmission of the data in a predetermined time interval. It is ascertained whether a transmission error exists in a communication line connecting the first storage device to the second storage device. If the transmission error exits, then the transmission unit is controlled to not perform the transmission of the data from the first storage device; otherwise the transmission unit is not controlled to not perform the transmission of the data from the first storage device.

Claims

1. A method for controlling a transmission of data from a first storage device to a second storage device, said first storage device including a recording unit for recording said data, a buffer for temporarily storing said data read from the recording unit, and a transmission unit for transmitting said data read from the buffer, said method comprising:

determining that sufficient buffer space in the buffer is not available for said transmission of said data in a predetermined time interval;

responsive to said detecting that said buffer space is not available, ascertaining whether a transmission error exists in a communication line connecting the first storage device to the second storage device;

if said ascertaining ascertains that said transmission error exists, then controlling the transmission unit to not perform said transmission of said data from the first storage device;

if said ascertaining ascertains that said transmission error does not exist, then not controlling the transmission unit to not perform said transmission of said data from the first storage device.

2. The method of claim 1, wherein said ascertaining whether the transmission error exists comprises:

determining a bandwidth of the communication line;

after determining the bandwidth, determining whether the bandwidth exceeds a threshold value;

if it is determined that the bandwidth does not exceed the threshold value or (if it is determined that the bandwidth exceeds the threshold value and the buffer has been continuously unavailable a predetermined number of times), then ascertaining that said transmission error exists;

if it is determined that the determined bandwidth exceeds the threshold value and the buffer has not been continuously unavailable the predetermined number of times, then increasing the time interval to a greater value and ascertaining that said transmission error does not exist.

3. The method of claim 2, wherein said determining the bandwidth is performed only if it has been determined that sufficient buffer space in the buffer is not available for said transmission of said data in said predetermined time interval.

4. The method of claim 2, wherein said determining the bandwidth of the communication line comprises:

receiving a control sigal from a switching device connected to the storage device via the communication line; and

determining the bandwidth from the control signal.

5. The method of claim 4, wherein said determining the bandwidth from the control signal comprises determining the bandwidth from a frequency at which the control signal is received from the switching device.

6. The method of claim 5, wherein when the control signal is received from the switching device, a ratio of free capacity to maximum capacity of an output buffer in the switching device is less than a specified reference ratio.

7. The method of claim 4, wherein the control signal includes only information for specifying the bandwidth.

8. A computer program product, comprising a computer-readable recording medium in which a computer readable program is stored, said program being adapted to be executed on a computer to perform a method for controlling a transmission of data from a first storage device to a second storage device, said first storage device including a recording unit for recording said data, a buffer for temporarily storing said data read from the recording unit, and a transmission unit for transmitting said data read from the buffer, said method comprising:

determining that sufficient buffer space in the buffer is not available for said transmission of said data in a predetermined time interval;

responsive to said detecting that said buffer space is not available, ascertaining whether a transmission error exists in a communication line connecting the first storage device to the second storage device;

if said ascertaining ascertains that said transmission error exists, then controlling the transmission unit to not perform said transmission of said data from the first storage device;

if said ascertaining ascertains that said transmission error does not exist, then not controlling the transmission unit to not perform said transmission of said data from the first storage device.

9. The computer program product of claim 8, wherein said ascertaining, whether the transmission error exists comprises:

determining a bandwidth of the communication line;

after determining the bandwidth, determining whether the bandwidth exceeds a threshold value;

if it is determined that the bandwidth does not exceed the threshold value or (if it is determined that the bandwidth exceeds the threshold value and the buffer has been continuously unavailable a predetermined number of times), then ascertaining that said transmission error exists;

if it is determined that the determined bandwidth exceeds the threshold value and the buffer has not been continuously unavailable the predetermined number of times, then increasing the time interval to a greater value and ascertaining that said transmission error does not exist.

10. The computer program product of claim 9, wherein said determining the bandwidth is performed only if it has been determined that sufficient buffer space in the buffer is not available for said transmission of said data in said predetermined time interval.

11. The computer program product of claim 9, wherein said determining the bandwidth of the communication line comprises:

receiving a control signal from a switching device connected to the storage device via the communication line; and

determining the bandwidth from the control signal.

12. The computer program product of claim 11, wherein said determining the bandwidth from the control signal comprises determining the bandwidth from a frequency at which the control signal is received from the switching device.

13. The computer program product of claim 12, wherein when the control signal is received from the switching device, a ratio of free capacity to maximum capacity of an output buffer in the switching device is less than a specified reference ratio.

14. The method of claim 12, wherein the control signal includes only information for specifying the bandwidth.

20. The apparatus of claim 10, wherein when the control signal is received from the switching device, a ratio of free capacity to maximum capacity of an output buffer in the switching device is less than a specified reference ratio.

15. An apparatus comprising a computer for executing a computer readable program to perform a method for controlling a transmission of data from a first storage device to a second storage device, said first storage device including a recording unit for recording said data, a buffer for temporarily storing said data read from the recording unit, and a transmission unit for transmitting said data read from the bluffer, said method comprising:

determining that sufficient buffer space in the buffer is not available for said transmission of said data in a predetermined time interval;

responsive to said detecting that said buffer space is not available, ascertaining whether a transmission error exists in a communication line connecting the first storage device to the second storage device;

if said ascertaining ascertains that said transmission error exists, then controlling the transmission unit to not perform said transmission of said data from the first storage device;

if said ascertaining ascertains that said transmission error does not exist, then not controlling the transmission unit to not perform said transmission of said data from the first storage device.

16. The apparatus of claim 15, wherein said ascertaining whether the transmission error exists comprises:

determining a bandwidth of the communication line;

after determining the bandwidth, determining whether the bandwidth exceeds, a threshold value;

if it is determined that the bandwidth docs not exceed the threshold value or (if it is determined that the bandwidth exceeds the threshold value and the buffer has been continuously unavailable a predetermines number of times), then ascertaining that said transmission error exists;

if it is determined that the determined bandwidth exceeds the threshold value and the buffer has not been continuously unavailable the predetermined number of times, then increasing the time interval to a greater value and ascertaining that said transmission error does not exist.

17. The apparatus of claim 16, wherein said determining the bandwidth is performed only if it has been determined that sufficient buffer space in the buffer is not available for said transmission of said data in said predetermined time interval.

18. The apparatus of claim 16, wherein said determining the bandwidth of the communication line comprises:

receiving a control signal from a switching device connected to the storage device via the communication line; and

determining the bandwidth from the control signal.

19. The apparatus of claim 18, wherein said determining the bandwidth from the control signal comprises determining the bandwidth from a frequency at which the control signal is received from the switching device.