Aggregated opportunistic lock and aggregated implicit lock management for locking aggregated files in a switched file system

• US 8,005,953 B2
• Filed: 05/19/2009
• Issued: 08/23/2011
• Est. Priority Date: 01/11/2001
• Status: Expired due to Term

• Current Assignee: RPX Corporation
• Original Assignee: F5 Networks, Inc. (F5 Incorporated)
• Inventors: Miloushev, Vladimir I., Nickolov, Peter A.
• Primary Examiner(s): DONAGHUE, LARRY D
• Application Number:
  US12/468,186
• Publication Number:
  US 20090234856A1
• Time in Patent Office: 826 Days
• Field of Search: 709223-226, 709/214, 710/200
• US Class Current: 709/225
• CPC Class Codes: G06F 11/1076 Parity data used in redundant arrays of independent storages, e.g. in RAID systems
• CPC Class Codes: G06F 11/2056 by mirroring
• CPC Class Codes: G06F 11/2058 using more than 2 mirrored copies
• CPC Class Codes: G06F 16/1824 implemented using Network-attached Storage [NAS] architecture distributed or networked storage systems G06F3/067; protocols for distributed storage of data in a network H04L67/1097
• CPC Class Codes: G06F 2211/1028 Distributed, i.e. distributed RAID systems with parity
• CPC Class Codes: H04L 67/06 specially adapted for file transfer, e.g. file transfer protocol [FTP]
• 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 67/1012 based on compliance of requirements or conditions with available server resources
• CPC Class Codes: H04L 67/1014 based on the content of a request
• 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 67/1023 based on a hash applied to IP addresses or costs
• CPC Class Codes: H04L 67/1029 using data related to the state of servers by a load balancer
• CPC Class Codes: H04L 67/1034 Reaction to server failures by a load balancer
• 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 67/56 Provisioning of proxy services store-and-forward switching systems in data switching networks H04L12/54
• CPC Class Codes: H04L 67/567 Integrating service provisioning from a plurality of service providers
• CPC Class Codes: H04L 69/22 : Parsing or analysis of headers
• CPC Class Codes: H04L 69/329 : in the application layer [OSI layer 7]
• CPC Class Codes: H04L 9/40 : Network security protocols

Abstract

A switched file system, also termed a file switch, is logically positioned between client computers and file servers in a computer network. The file switch distributes user files among multiple file servers using aggregated file, transaction and directory mechanisms. The file switch supports caching of a particular aggregated data file either locally in a client computer or in the file switch in accordance with the exclusivity level of an opportunistic lock granted to the entity that requested caching. The opportunistic lock can be obtained either on the individual data files stored in the file servers or on the metadata files that contain the location of each individual data files in the file servers. The opportunistic lock can be broken if another client tries to access the aggregated data file. Opportunistic locks allows client-side caching while preserving data integrity and consistency, hence the performance of the switched file system is increased.

Claims

1. A method of caching data from user files stored in shared data computer network, where each user file of at least a plurality of the user files is divided into portions stored on a plurality of file servers, among a group of file servers in a computer network, comprising:

receiving a user request to access a subset of a specified user file, the request including a request for an opportunistic lock on the subset of the specified user file;

identifying a subset of file servers that store portions of the user file that together comprise the subset of the specified user file;

sending an oplock request to each file server in the subset of file servers, and receiving oplock request replies from the subset of file servers;

aggregating the received oplock request replies to produce an aggregated oplock reply, such that the aggregated oplock reply is an oplock grant only when all the received oplock request replies are oplock grants; and

sending the aggregated oplock reply to a sender of the user request, thereby enabling the sender to cache data from the subset of the specified user file only when the aggregate oplock reply is an oplock grant.

2. The method of claim 1, further including:

receiving an oplock break from a respective file server in the set of file servers;

forwarding the oplock break to the sender of the user request.

3. The method of claim 1, further including:

waiting to receive an oplock break acknowledgement from the sender of the user request, and upon receiving the oplock break acknowledgement from the sender of the user request, forwarding the oplock break acknowledgement to the respective file server in the set of file servers.

4. The method of claim 1, further including:

upon receiving the oplock break, disabling caching of data from the subset of the specified user file.

5. The method of claim 1, further including:

upon receiving the oplock break, disabling caching of data from the subset of the specified user file within a file switch logically positioned between the sender of the user request and the set of file servers.

6. A method of caching data from user files stored in shared data computer network, where each user file of at least a plurality of the user files is divided into portions stored on a plurality of file servers, among a group of file servers in a computer network, comprising:

receiving a user request to access a specified user file, the request including a request for an opportunistic lock on the specified user file;

accessing metadata identifying a set of file servers for storing respective defined portions of the specified user file;

identifying, based on the metadata, a subset of the file servers that store portions of the user file that together comprise the specified user file;

sending an oplock request to each file server in the subset of file servers, and receiving oplock request replies from the subset of file servers;

aggregating the received oplock request replies to produce an aggregated oplock reply, such that the aggregated oplock reply is an oplock grant only when all the received oplock request replies are oplock grants; and

sending the aggregated oplock reply to a sender of the user request, thereby enabling the sender to cache data from the subset of the specified user file only when the aggregate oplock reply is an oplock grant.

7. The method of claim 6, further including:

receiving an oplock break from a respective file server in the set of file servers;

forwarding the oplock break to the sender of the user request.

8. The method of claim 7, further including:

waiting to receive an oplock break acknowledgement from the sender of the user request, and upon receiving the oplock break acknowledgement from the sender of the user request, forwarding the oplock break acknowledgement to the respective file server in the set of file servers.

9. The method of claim 7, further including:

upon receiving the oplock break, disabling caching of data from the subset of the specified user file.

10. The method of claim 7, further including:

upon receiving the oplock break, disabling caching of data from the subset of the specified user file within a file switch logically positioned between the sender of the user request and the set of file servers.

11. The method of claim 6, the accessing metadata step including accessing a metafile that stores information identifying a set of file servers for storing respective defined portions of the specified user file.