ASYNCHRONOUS FILE REPLICATION AND MIGRATION IN A STORAGE NETWORK

• US 20070022122A1
• Filed: 07/25/2006
• Published: 01/25/2007
• Est. Priority Date: 07/25/2005
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Parascale Incorporated (Hitachi, Ltd.)
• Inventors: Nalam, Naveen, Oskouy, Rasoul, Zafman, David, Bahar, Cameron, Hopfield, Joseph
• Granted Patent: US 7,571,168 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 16/184 implemented as replicated file system
• CPC Class Codes: G06F 2209/508 Monitor
• CPC Class Codes: G06F 9/5011 the resources being hardware resources other than CPUs, Servers and Terminals
• CPC Class Codes: G06F 9/5016 the resource being the memory
• CPC Class Codes: H04L 61/50 Address allocation
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• 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 67/1017 based on a round robin mechanism
• CPC Class Codes: H04L 67/1029 using data related to the state of servers 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 67/563 Data redirection of data network streams
• CPC Class Codes: Y10S 707/99931 Database or file accessing
• CPC Class Codes: Y10S 707/99952 Coherency, e.g. same view to multiple users
• CPC Class Codes: Y10S 707/99953 Recoverability

Abstract

File system independent techniques and mechanisms for replicating files on multiple devices are provided, migrating files from one device to another (for purposes of reliability, increased bandwidth, load balancing, capacity expansion, or reduced cost), and propagating updates from a master copy to remote replicas. The mechanisms involve work queues and asynchronous file migration daemons that operate independently from and in parallel with the primary client-server and network protocol to on-disk storage data paths.

Claims

1. A method of performing remote file operations, the method comprising:

receiving a file task description that identifies a remote file, an operation to be performed, and a current status associated with the file task description;

providing a set of persistent work queues associated with a plurality of storage servers that include one or more file task descriptions;

providing an elected work manager configured to accept remote file operation requests and to translate the requests into one or more corresponding tasks to be placed in the set of work queues; and

providing a background replication agent associated with each storage server in the plurality of storage servers, a background replication agent configured to monitor a work queue in the set of work quest for an associated storage server, to accept requests in the work queue, to perform the accepted tasks using file system independent mechanisms, and to update the completion status of each accepted task.

2. The method of claim 1 wherein a file task description associated with replication is implemented by performing a remote copy, awaiting confirmation, and updating a file location map to reflect the existence of a new copy of a file.

3. The method of claim 1 wherein a file task description associated with migration is implemented by performing a remote copy, awaiting confirmation, updating a file location map to reflect a new file location, and performing a remote delete of the original file.

4. The method of claim 1 wherein a file task description associated with file update propagation is implemented by performing a remote copy operation to update each existing replica.

5. The method of claim 1 wherein a file task description associated with delete propagation is implemented by performing a remote delete operation on each existing replica.