Namespace Server Referral Redirection for Transparent File Migration

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Solution Overview

Problem

Existing data storage systems face challenges in integrating multiple storage servers of different types into a single network while maintaining transparent file migration and high-speed client access.

Innovation Solution

A namespace server coordinates file access using the NFS or CIFS protocol, managing a virtual file system by determining if files are being migrated and redirecting clients to appropriate file servers, ensuring non-disruptive migration and high-speed access through file mapping protocols.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If global virtualization capabilities are used to integrate multiple storage servers, then storage system integration and scalability are improved, but device complexity increases

Engineering Contradiction:

Improvestorage system integrationVSAvoidnamespace management complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent introduces a namespace server as an intermediary component that sits between clients and multiple storage servers. This namespace server manages the global virtual namespace and handles mapping between global file names and local file system paths, thereby integrating multiple storage servers without requiring clients to directly manage the complexity of multiple storage systems.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent divides the storage system into distinct components: a namespace server that manages the global virtual namespace and multiple file servers that manage local file systems. This segmentation allows each component to handle specific tasks independently, improving integration while managing complexity through clear separation of concerns.

Inventive Principle:

Principle #1Segmentation

2Productivity

If file migration is implemented across multiple storage servers, then load balancing and capacity management are improved, but transparency of migration to clients becomes difficult to maintain

Engineering Contradiction:

Improveload balancingVSAvoidmigration transparency

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent implements file migration by creating a copy of the file at the destination storage server while maintaining the original file at the source. The namespace server updates its mapping to point to the new location, and clients continue to access files through the same global file names without being aware of the migration. This copying approach ensures load balancing while maintaining migration transparency.

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The namespace server acts as a mediator that abstracts the migration process from clients. When files are migrated between storage servers, the namespace server handles the mapping updates and redirects client requests appropriately, ensuring that migration occurs transparently without clients needing to know about the underlying file movement.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Speed

If clients use file mapping protocols for high-speed block access, then access speed is improved, but migration of files becomes non-transparent to clients

Engineering Contradiction:

Improveblock access speedVSAvoidmigration transparency

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The namespace server serves as an intermediary that intercepts file mapping requests from clients and redirects them to the appropriate file servers based on the current location of files. This allows clients to use high-speed block access protocols while the namespace server ensures migration transparency by updating mappings and redirecting requests without clients being aware of file movements.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent implements dynamic file mapping where the namespace server continuously updates the mapping between global file names and local file system paths as files are migrated. This dynamic approach allows clients to maintain high-speed block access while the underlying file locations change transparently through the namespace server's redirection capability.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS7937453B1Scalable global namespace through referral redirection at the mapping layer

Publication Date: 2011.05.03 EMC IP HLDG CO LLC

AI summary

Client computers, a namespace server, and file servers are linked in a data network so that the namespace server provides the clients with NFS or CIFS access to a virtual file system including files stored in the file servers, and also provides migration of files between the file servers in a fashion transparent to the client access using NFS or CIFS. The client computers and storage arrays storing the file data are also linked in a storage area network so that the clients have high speed block access to the file data using a file mapping protocol. The namespace server redirects a metadata access request in the file mapping protocol from a client to the appropriate file server when the file is not being migrated, and otherwise denies the metadata access request when the file is being migrated so that the client reverts to NFS or CIFS access.