Expander-based solution to the dynamic STP address problem
View Patent ↗The persistent binding of STP SAS addresses to SATA devices is disclosed so that SATA devices can be moved to different insertion points (ports) within a SAS expander and still properly receive I/O requests. When a SATA device is inserted into the SAS expander, it is interrogated to obtain information about the attached device. This information may be combined using a hashing function to obtain a unique ID for the SATA device. A table can be used to assign a STP SAS address to the Phy connected to the device based in the unique ID. In this manner, the same STP SAS address will be assigned to the Phy connected to a particular SATA device, regardless of where the device is connected to the SAS expander.
1. A Serial Attached SCSI (SAS) expander for persistent binding of a connected Serial Advanced Technology Attachment (SATA) device to a SATA Tunneling Protocol (STP) SAS address, comprising:
a processor programmed for
detecting that the SATA device has been connected to a Phy in the SAS expander,
obtaining information about the SATA device, and
generating a unique ID for the SATA device based on the obtained information; and
memory communicatively coupled to the processor and configured for associating the unique ID with a corresponding STP SAS address utilizing a stored table;
wherein the processor is further programmed for assigning the corresponding STP SAS address to the Phy connected to the SATA device.
2. The SAS expander of claim 1 , the processor further programmed for obtaining information about the SATA device using IDENTIFY exchanges.
3. The SAS expander of claim 1 , the obtained information including a World Wide Name (WWN) of the SATA device.
4. The SAS expander of claim 1 , the processor further programmed for using a hashing table to generate the unique ID from the obtained information.
5. The SAS expander of claim 1 , the processor further programmed for creating a new entry in the stored table if the unique ID is not found in the table.
6. The SAS expander of claim 1 , the processor further programmed for associating a previously used STP SAS address with the unique ID if the unique ID is not found in the table.
7. The SAS expander of claim 1 , further comprising one or more initiators and one or more devices coupled to the SAS expander.
8. A storage network comprising the SAS expander of claim 1 .
9. A Serial Attached SCSI (SAS) expander for persistent binding of a connected Serial Advanced Technology Attachment (SATA) device to a SATA Tunneling Protocol (STP) SAS address, comprising:
means for detecting that the SATA device has been connected to a Phy in the SAS expander;
means for obtaining information about the SATA device;
means for generating a unique ID for the SATA device based on the obtained information;
means for associating the unique ID with a corresponding STP SAS address; and
means for assigning the corresponding STP SAS address to the Phy connected to the SATA device.
10. A method for persistent binding of a connected Serial Advanced Technology Attachment (SATA) device to a SATA Tunneling Protocol (STP) SAS address in a SAS expander, comprising:
detecting that the SATA device has been connected to a Phy in the SAS expander;
obtaining information about the SATA device;
generating a unique ID for the SATA device based on the obtained information;
associating the unique ID with a corresponding STP SAS address utilizing a stored table; and
assigning the corresponding STP SAS address to the Phy connected to the SATA device.
11. The method of claim 10 , further comprising obtaining information about the SATA device using IDENTIFY exchanges.
12. The method of claim 10 , the obtained information including a World Wide Name (WWN) of the SATA device.
13. The method of claim 10 , further comprising using a hashing table to generate the unique ID from the obtained information.
14. The method of claim 10 , further comprising creating a new entry in the stored table if the unique ID is not found in the table.
15. The method of claim 10 , further comprising associating a previously used STP SAS address with the unique ID if the unique ID is not found in the table.
16. A computer-readable medium comprising program code for persistent binding of a connected Serial Advanced Technology Attachment (SATA) device to a SATA Tunneling Protocol (STP) SAS address in a SAS expander, the program code for causing performance of a method comprising:
detecting that the SATA device has been connected to a Phy in the SAS expander;
obtaining information about the SATA device;
generating a unique ID for the SATA device based on the obtained information;
associating the unique ID with a corresponding STP SAS address utilizing a stored table; and
assigning the corresponding STP SAS address to the Phy connected to the SATA device.
17. The computer-readable medium of claim 16 , the program code further for causing performance of a method comprising obtaining information about the SATA device using IDENTIFY exchanges.
18. The computer-readable medium of claim 16 , the obtained information including a World Wide Name (WWN) of the SATA device.
19. The computer-readable medium of claim 16 , the program code further for causing performance of a method comprising using a hashing table to generate the unique ID from the obtained information.
20. The computer-readable medium of claim 16 , the program code further for causing performance of a method comprising creating a new entry in the stored table if the unique ID is not found in the table.
21. The computer-readable medium of claim 16 , the program code further for causing performance of a method comprising associating a previously used STP SAS address with the unique ID if the unique ID is not found in the table.