Server identification assignment in a distributed switched storage environment

• US 8,176,156 B1
• Filed: 12/12/2003
• Issued: 05/08/2012
• Est. Priority Date: 12/12/2003
• Status: Active Grant

• Current Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Original Assignee: EMC Corporation (Dell Technologies Inc.)
• Inventors: Sullivan, Douglas
• Primary Examiner(s): Shin, Kyung H
• Application Number:
  US10/735,432
• Time in Patent Office: 3,070 Days
• Field of Search: 709/223, 709/201
• US Class Current: 709/223
• 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]

Abstract

A method and apparatus are provided for assigning/obtaining enclosure identification numbers in a distributed switch storage system. The method takes advantage a network topology wherein one port on the switch is always used as a downstream connection (towards a control station) and one always used as an upstream connection (away from the control station). Using single-hop type packets an assignment arbitration protocol ensures that each enclosure is assigned a unique and predictable Enclosure ID.

Claims

1. A scalable network attached storage system comprising:

at least one enclosure, the enclosure including at least one storage blade and a switch having a first port for communicating with an upstream enclosure and a second port for communicating with a downstream device, the enclosure further comprising a storage device for storing an identification number of the at least one enclosure, wherein each of the plurality of enclosures has a corresponding identifier, wherein at any point during operation of the system at the command of a control station each enclosure discovers its neighboring devices to determine which enclosure has the control station as a neighboring device, and wherein a first enclosure having the control station as a neighboring device assigns itself a first identification number and sends the first identification number to a second enclosure downstream from the first enclosure, wherein the second enclosure upon receiving the first identification number assigns itself a second identification number, wherein the second enclosure derives the second identification number by performing a function on the first identification number and each subsequent enclosure assigns itself a value as its identification number, wherein the value is derived by performing the function on an identification number received from an immediately preceding enclosure.

2. The scalable network of claim 1, further comprising a backplane, for coupling the at least one enclosure, the backplane comprising a storage device for storing a copy of the identification number of the at least one enclosure.

3. The scalable network of claim 1, wherein the function performed on a value received from an immediately preceding enclosure includes incrementing the value.

4. A network attached storage system including:

a control station; and

a plurality of enclosures, the enclosures comprising at least one storage blade and a switch, the enclosures being coupled in a chain, with a first enclosure in the chain being directly connected to the control station, wherein each of the plurality of enclosures has a corresponding identifier, wherein at any point during operation of the system at the command of a control station each enclosure discovers its neighboring devices to determine which enclosure has the control station as a neighboring device, wherein the first enclosure having the control station as a neighboring device assigns itself a first identification number and sends the first identification number to a second enclosure downstream from the first enclosure, wherein the second enclosure upon receiving the first identification number assigns itself a second identification number, wherein the second enclosure derives the second identification number by performing a function on the first identification number and each subsequent enclosure assigns itself a value as its identification number, wherein the value is derived by performing the function on an identification number received from an immediately preceding enclosure.

5. The network of claim 4, wherein the value of an identifier for a given enclosure in the chain is assigned responsive to a value of an identifier of an enclosure immediately preceding the given enclosure in the chain.

6. The network attached storage system of claim 4 further comprising a backplane, coupled to the plurality of enclosures, the backplane including a device for storing a copy of each identifier for the plurality of enclosures.