Switching system

• US 6,985,956 B2
• Filed: 11/02/2001
• Issued: 01/10/2006
• Est. Priority Date: 11/02/2000
• Status: Expired due to Term

• Current Assignee: Oracle America, Inc. (Oracle Corporation)
• Original Assignee: Sun Microsystems Incorporated (Oracle Corporation)
• Inventors: Hall, Howard, Merhar, Milan, Ferrari, Stephen, Cochrane, Christopher, Luke, Stanley, Condylis, Mitchell
• Primary Examiner(s): Jean, Frantz B.
• Application Number:
  US10/415,327
• Publication Number:
  US 20040133634A1
• Time in Patent Office: 1,530 Days
• Field of Search: 709/216, 709/217, 709/219, 709/223, 709/226, 709/229, 709/238, 709/203, 709/212, 710/31, 710/316, 710/308
• US Class Current: 709/229
• CPC Class Codes: G06F 11/1435 using file system or storage system metadata
• CPC Class Codes: G06F 11/1464 for networked environments
• CPC Class Codes: G06F 11/1658 Data re-synchronization of a redundant component, or initial sync of replacement, additional or spare unit
• CPC Class Codes: G06F 11/2056 by mirroring
• CPC Class Codes: G06F 11/2069 Management of state, configuration or failover
• CPC Class Codes: G06F 11/2089 Redundant storage control functionality
• CPC Class Codes: G06F 11/2094 Redundant storage or storage space G06F11/2056 takes precedence
• CPC Class Codes: G06F 11/2097 maintaining the standby controller/processing unit updated initialisation or re-synchronisation thereof G06F11/1658 and subgroups
• CPC Class Codes: H04L 49/357 Fibre channel switches
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• CPC Class Codes: H04L 67/10015 Access to distributed or replicated servers, e.g. using brokers
• CPC Class Codes: H04L 67/1008 based on parameters of servers, e.g. available memory or workload monitoring of computer activity G06F11/30
• CPC Class Codes: H04L 67/101 based on network conditions
• CPC Class Codes: H04L 67/1017 based on a round robin mechanism
• CPC Class Codes: H04L 67/1019 Random or heuristic server selection
• CPC Class Codes: H04L 67/1095 Replication or mirroring of data, e.g. scheduling or transport for data synchronisation between network nodes
• 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 67/14 Session management for real-time applications in data packet communications networks H04L65/1066
• CPC Class Codes: H04L 67/63 Routing a service request depending on the request content or context
• CPC Class Codes: H04L 69/16 Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]
• CPC Class Codes: H04L 69/161 : Implementation details of TCP/IP or UDP/IP stack architecture; Specification of modified or new header fields
• CPC Class Codes: H04L 69/165 : Combined use of TCP and UDP protocols; selection criteria therefor
• CPC Class Codes: H04L 69/329 : in the application layer [OSI layer 7]
• CPC Class Codes: H04L 9/40 : Network security protocols

Abstract

Methods and systems consistent with certain aspects related to the present invention provide a digital network having a plurality of data storage elements, at least one client, and a switch element. The switch element may be operable to receive access requests from the client and provide access to data on the storage elements in response to one or more access requests.

Claims

1. In a digital network comprising a plurality of data storage elements, at least one client, and a switch element operable to receive access requests from the client and provide access to data on the storage elements in response to the access requests, a method of managing storage on the data storage elements, the method comprising:

providing, within the switch element,

a first configurable set of processor elements to process storage resource connection requests,

a second configurable set of processor elements capable of communications with the first configurable set of processor elements to receive, from the first configurable set of processor elements, storage connection requests representative of client requests, and to route the requests to at least one of the storage elements, and

a configurable switching fabric interconnected between the first and second sets of processor elements, for receiving at least a first storage connection request from one of the first set of processor elements, determining an appropriate one of the second set of processors for processing the storage connection request, automatically configuring the storage connection request in accordance with a protocol utilized by the selected one of the second set of processors, and forwarding the storage connection request to the selected one of the second set of processors for routing to at least one of the storage elements,

configuring, within the switch element, a replicated storage domain including connections to a set of storage elements;

replicating at least a subset of data stored on one storage element of the domain to all other storage elements in the replicated storage domain;

configuring the switch element to receive file system requests from at least one client; and

upon receipt of a request whose execution would result in modification of data stored in a storage element, operating the switch element to transmit the request to at least a set of storage elements in the replicated storage domain.

2. The method of claim 1 wherein the request is a READ request.

3. The method of claim 1 further comprising:

configuring the switch element to obtain, in response to transmission of the request, a transaction confirmation from storage elements in the replicated storage domain to which the request has been transmitted.

4. The method of claim 3 further comprising:

transmitting back to the originating client the obtained transaction confirmation.

5. The method of claim 4 wherein the obtaining of a transaction confirmation comprises:

transmitting back to the originating client the first response received from the storage element.

6. The method of claim 4 wherein the obtaining of a transaction confirmation comprises:

defining a quorum constituting a selected percentage of the storage elements;

waiting for a selected fraction of storage elements to respond with identical response messages in response to transmission of the request, and

upon receipt of identical response messages from the quorum, transmitting the response back to the originating client.

7. The method of claim 1 further comprising:

monitoring responsiveness of storage elements in the replicated storage domain; and

upon detection of an unresponsive storage element, removing the unresponsive storage element from the replicated storage domain.

8. In a digital network comprising a plurality of storage servers, at least one client, and a switch element operable to receive Network File Service (NFS) access requests from the client and provide access to data on the storage servers in response to the NFS access requests, a method of providing replicated storage on the storage servers, the method comprising:

replicating at least a subset of data on a Network Attached Storage (NAS) server on at least one other NAS server to create a replicated storage domain;

receiving file system requests from at least one client;

if the file system request is a write request,

(1) multicasting the write request to each of the individual servers included in the replicated storage domain, to maintain substantial data synchronization across the replicated storage domain, and

(2) receiving, from at least one of the servers in the replicated storage domain, a response to the received file system request;

wherein;

the subset of data comprises an active file system including data files having modes associated therewith;

the set of NAS servers in the replicated storage domain comprises a file system server set;

requests are communicated as digital packets, at least a subset of packets including information representative of requests for inode creation or destruction; and

the multicasting step includes the step of multicasting to the entire active file system server set all inode creation and destruction packets.

9. The method of claim 8 wherein the multicast packets contain a sequence number identifying any of transaction source or destination.

10. The method of claim 8 further comprising:

monitoring access within the file system server set; and

if access exceeds a predetermined threshold, adding at least one additional server to the file system server set.

11. The method of claim 8 further comprising:

monitoring access within the file system server set; and

if access falls below a predetermined threshold, removing at least one server from the file system server set.

12. The method of claim 8 further comprising:

monitoring access within the file system server set on a per-file basis for a given file; and

if access to the at least one file exceeds a predetermined threshold, creating additional copies of the file.

13. The method of claim 8 further comprising:

monitoring access within the file system server set; and

in response to a detected level of access requests, creating partial file system copies.

14. In a digital network comprising a plurality of storage servers, at least one client, and a switch element operable to receive Network File Service (NFS) access requests from the client and provide access to data on the storage servers in response to the NFS access requests, a method of providing replicated storage on the storage servers, the method comprising:

replicating at least a subset of data on a Network Attached Storage (NAS) server on at least one other NAS server to create a replicated storage domain;

receiving file system requests from at least one client;

if the file system request is a write request,

(1) multicasting the write request to each of the individual servers included in the replicated storage domain, to maintain substantial data synchronization across the replicated storage domain, and

(2) receiving, from at least one of the servers in the replicated storage domain, a response to the received file system request;

wherein;

the subset of data comprises an active file system including data files having modes associated therewith;

the set of NAS servers in the replicated storage domain comprises a file system server set;

requests are communicated as digital packets, at least a subset of packets including information representative of requests for inode creation or destruction;

the multicasting step includes the step of multicasting to the entire active file system server set all inode creation and destruction packets; and

configuring a NAS coherency manager (NCM) operable to control the replicating and multicasting.

15. The method of claim 14 further comprising:

configuring the NCM to provide dynamically distributed, mirrored storage content to a plurality of clients.

16. The method of claim 14 further comprising:

configuring the NCM to coordinate an initial mirrored status of storage servers within the replicated storage domain.

17. The method of claim 14 further comprising:

configuring the NCM to respond to any of a notification that a storage server has been removed from the replicated storage domain or has become available.

18. The method of claim 14 further comprising:

configuring the NCM to monitor and maintain synchronization of file system contents between and among storage servers in the replicated storage domain.

19. The method of claim 18 further comprising configuring the NCM to:

detect server-to-server asynchrony within the replicated storage domain; and

in response to detected asynchrony, synchronize the servers.

20. The method of claim 18 further comprising:

configuring the NCM to transmit to a load balancing element a list of allocated inode and content inode lists.

21. The method of claim 18 further comprising:

maintaining file handle usage maps on a per file system basis, the file handle usage maps representative of all allocated inodes on a server, and all inodes with content present on the server, respectively.

22. The method of claim 18 further comprising:

providing volume block-level mirroring to generate a copy of a data volume from a source to a target NAS.

23. In a digital network comprising a plurality of data storage elements, at least one client, and a switch element operable to receive access requests from the client and provide access to data on the storage elements in response to the access requests, a method of managing storage on the data storage elements, the improvement comprising:

a first configurable set of processor elements to process storage resource connection requests,

a second configurable set of processor elements capable of communications with the first configurable set of processor elements to receive, from the first configurable set of processor elements, storage connection requests representative of client requests, and to route the requests to at least one of the storage elements, and

a configurable switching fabric interconnected between the first and second sets of processor elements, for

receiving at least a first storage connection request from one of the first set of processor elements,

determining an appropriate one of the second set of processors for processing the storage connection request,

automatically configuring the storage connection request in accordance with a protocol utilized by the selected one of the second set of processors, and

forwarding the storage connection request to the selected one of the second set of processors for routing to at least one of the storage elements,

means for configuring, within the switch element, a replicated storage domain including connections to a set of storage elements;

means for replicating at least a subset of data stored on one storage element of the domain to all other storage elements in the replicated storage domain;

means for configuring the switch element to receive file system requests from at least one client; and

means for, upon receipt of a request whose execution would result in modification of data stored in a storage element, operating the switch element to transmit the request to at least a set of storage elements in the replicated storage domain.