Method and apparatus for identifying one or more devices having faults in a communication loop

• US 20040039981A1
• Filed: 08/23/2002
• Published: 02/26/2004
• Est. Priority Date: 08/23/2002
• Status: Active Grant

• Current Assignee: NetApp, Inc.
• Original Assignee: LSI Logic Corporation (Broadcom, Inc.)
• Inventors: Lynn, James A., Riedl, Daniel A., Gitchell, Anthony D.
• Granted Patent: US 7,007,191 B2
• Time in Patent Office: Days
• US Class Current: 714/758
• CPC Class Codes: H04L 1/243 at the transmitter, using a loop-back
• CPC Class Codes: H04L 12/437 Ring fault isolation or reconfiguration for SDH/SONET ring networks H04J3/085
• CPC Class Codes: H04L 41/06 Management of faults, events, alarms or notifications
• CPC Class Codes: H04L 43/0817 by checking functioning

Abstract

A system identifies one or more devices having faults in a communication loop. The system includes an interface, a decision module, and a connection processor. The interface is configured for sending requests for information to each device of the communication loop and for receiving responses to the requests. The devices may include computer disk drives for use in a storage system. The requests may include Read-Link Status (RLS) commands sent to the computer disk drives. The RLS commands may provide diagnostics of the disk drives connected to the loop. The decision module is communicatively connected to the interface for weighting the responses of each device to identify the devices having the faults. The responses may be weighted based on the relative potential for disrupting operability of the system. The communication loop may include an FC loop that allows communications between a host system and the computer disk drives.

Claims

1. A method of identifying one or more devices having faults in a communication loop, including steps of:

sending requests for information to each device of the communication loop;

receiving responses to the requests;

weighting the responses of each device to generate weighted responses of each device; and

processing the weighted responses of each device to identify the devices having the faults.

2. The method of claim 1, wherein the step of sending includes a step of issuing a Read Link Status command to each device.

3. The method of claim 1, wherein the method is iteratively performed.

4. The method of claim 1, wherein the step of receiving includes a step of determining error categories of the responses.

5. The method of claim 4, wherein the step of determining error categories includes a step of determining at least one of a link failure, a loss of synchronization, a loss of signal, a primitive sequence protocol error, an invalid transmission word, and an invalid Cyclic Redundancy Check.

6. The method of claim 4, wherein the step of weighting includes a step of assigning values to each of the error categories.

7. The method of claim 4, further including a step of determining a baseline of the weighted responses based on the error categories of the responses.

8. The method of claim 1, further including a step of bypassing the devices having the faults.

9. A system for identifying one or more devices having faults in a communication loop, including:

an interface configured for sending requests for information to each device of the communication loop and for receiving responses to the requests; and

a decision module communicatively connected to the interface for generating weighted responses of each device and processing the weighted responses to identify the devices having the faults.

10. The system of claim 9, further including a connection processor communicatively connected to the decision module for bypassing the devices having the faults.

11. The system of claim 9, wherein at least one of the devices includes a storage device.

12. The system of claim 9, wherein the communication loop includes a fibre channel.

13. A system for identifying one or more devices having faults in a communication loop, including:

means for sending requests for information to each device of the communication loop;

means for receiving responses to the requests; and

means for weighting the responses of each device to generate weighted responses of each device; and

means for processing the weighted responses of each device to identify the devices having the faults.

14. The system of claim 13, wherein the means for sending includes means for issuing a Read Link Status command to each device.

15. The system of claim 13, further including means for iteratively controlling the means for sending, receiving, and weighting.

16. The method of claim 13, wherein the means for receiving includes means for determining error categories of the responses.

17. The system of claim 16, wherein the means for determining error categories includes means for determining at least one of a link failure, a loss of synchronization, a loss of signal, a primitive sequence protocol error, an invalid transmission word, and an invalid Cyclic Redundancy Check.

18. The system of claim 16, wherein the means for weighting includes means for assigning values to each of the error categories.

19. The system of claim 16, further including means for determining a baseline of the weighted responses based on the error categories of the responses.

20. The system of claim 13, further including means for bypassing the devices having the faults.