SAS FABRIC DISCOVERY

• US 20130246683A1
• Filed: 03/13/2012
• Published: 09/19/2013
• Est. Priority Date: 03/13/2012
• Status: Active Grant

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: Michael G. Myrah
• Inventors: Natrajan, Balaji, Myrah, Michael G., Puttaiah, Pruthviraj Herur
• Granted Patent: US 9,081,818 B2
• Time in Patent Office: Days
• US Class Current: 710/316
• CPC Class Codes: G06F 11/3051 Monitoring arrangements for monitoring the configuration of the computing system or of the computing system component, e.g. monitoring the presence of processing resources, peripherals, I/O links, software programs verification or detection of system hardware configuration G06F11/2247
• CPC Class Codes: G06F 13/4045 where the bus bridge performs an extender function
• CPC Class Codes: G06F 13/4295 using an embedded synchronisation

Abstract

An example method of the present disclosure includes (i) creating, by a first serial attached SCSI (SAS) switch, a first topology map describing a portion of a SAS fabric associated with the first SAS switch; (ii) receiving, at the first SAS switch and from a second SAS switch, a second topology map describing a portion of the SAS fabric associated with the second SAS switch; and (iii) merging, by the first SAS switch, the first topology map and the second topology map to produce a consolidated topology map of the SAS fabric.

Claims

1. A serial attached SCSI (SAS) switch comprising:

a discovery module to

perform a local discovery operation on a portion of a SAS fabric associated with the SAS switch;

create a first local topology map based at least in part on a result of the local discovery operation;

request a second local topology map from an adjacent SAS switch;

receive the second local topology map from the adjacent SAS switch; and

create a consolidated topology map by merging the first local topology map with the second local topology map received from the adjacent SAS switch.

2. The SAS switch of claim 1, wherein the SAS switch and the adjacent SAS switch are trunked together.

3. The SAS switch of claim 1, wherein the local discovery operation does not extend beyond a trunk edge.

4. The SAS switch of claim 1, wherein the discovery module is further to set a flag when the local discovery operation is complete.

5. The SAS switch of claim 1, wherein the SAS switch requests the second local topology map from the adjacent SAS switch after receiving an indication from the adjacent SAS switch that the adjacent SAS switch has completed a local discovery operation.

6. The SAS switch of claim 1, wherein the discovery module is further to, after creating the consolidated topology map, send a SAS primitive indicating that a change occurred.

7. The SAS switch of claim 1, wherein the SAS switch comprises a chassis and plurality of expanders, and wherein one of the plurality of expanders comprises the discovery module, or wherein the discovery module resides on the SAS switch external to the plurality of expanders.

8. A non-transitory computer-readable medium comprising instructions that when executed cause a first serial attached SCSI (SAS) switch to:

perform a local discovery operation on a fabric that does not extend beyond a second SAS switch;

create a first topology map based at least in part on a result of the local discovery operation;

obtain a second topology map from the second SAS switch; and

merge the first topology map and second topology map to create a consolidated topology map.

9. The non-transitory computer-readable medium of claim 8, wherein the instructions further cause the first SAS switch to request the local discovery status of the second SAS switch prior to obtaining the second topology map from the second SAS switch.

10. The non-transitory computer-readable medium of claim 8, wherein the first SAS switch and second SAS switch are adjacent SAS switches that are trunked together.

11. The non-transitory computer-readable medium of claim 8, wherein the instructions further cause the first SAS switch to determine whether the second SAS switch has completed a local discovery operation.

12. The non-transitory computer-readable medium of claim 8, wherein the first and second topology maps describe the connective relationship between one or more PHYs, switches, expanders, hard disk drives, tape drives, host bus adapters, and controllers.

13. The non-transitory computer-readable medium of claim 8, wherein the instructions further cause the first SAS switch to send a SAS primitive indicating that a change occurred after creating the consolidated topology map.

14. The non-transitory computer-readable medium of claim 8, wherein the instructions cause the first SAS switch to perform the local discovery operation that does not extend beyond the second SAS switch by marking a SAS address of the second SAS switch when the second SAS switch is discovered and not conducting discovery on a fabric associated with the second SAS switch.

15. The non-transitory computer-readable medium of claim 8, wherein the first topology map, second topology map, and consolidated topology map are based at least in part on the composite design pattern software construct.

16. The non-transitory computer-readable medium of claim 8, wherein the instructions further cause the first switch to:

obtain a Nth topology map from a Nth SAS switch; and

merge the first topology map, the second topology map, and the Nth topology map to create the consolidated topology map.

17. A method comprising:

creating, by a first serial attached SCSI (SAS) switch, a first topology map describing a portion of a SAS fabric associated with the first SAS switch;

receiving, at the first SAS switch and from a second SAS switch, a second topology map describing a portion of the SAS fabric associated with the second SAS switch; and

merging, by the first SAS switch, the first topology map and the second topology map to produce a consolidated topology map of the SAS fabric.

18. The method of claim 17, further comprising conducting, by the first SAS switch, a local discovery operation on the SAS fabric, wherein the local discovery operation does not extend beyond the second SAS switch.

19. The method of claim 18, further comprising setting, by the first SAS switch, a flag when the local discovery operation is complete.

20. The method claim 17, further comprising determining, by the first SAS switch, when a local discovery operation of the second SAS switch is complete.