Servicing of Network Software Components of Nodes of a Cluster Storage System

Abstract

Described herein are method and apparatus for servicing software components of nodes of a cluster storage system. During data-access sessions with clients, client IDs and file handles for accessing files are produced and stored to clients and stored (as session data) to each node. A serviced node is taken offline, whereby network connections to clients are disconnected. Each disconnected client is configured to retain its client ID and file handles and attempt reconnections. Session data of the serviced node is made available to a partner node (by transferring session data to the partner node). After clients have reconnected to the partner node, the clients may use the retained client IDs and file handles to continue a data-access session with the partner node since the partner node has access to the session data of the serviced node and thus will recognize and accept the retained client ID and file handles.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is a continuation of U.S. patent application Ser. No. 12 / 372,637, filed Feb. 17, 2009 and titled “Servicing of Network Software Components of Nodes of a Cluster Storage System,” now allowed and issued on Apr. 26, 2016 as U.S. Pat. No. 9,325,790, the contents of which are hereby incorporated by reference.FIELD OF THE INVENTION[0002]The present invention relates to storage systems, and particularly, to servicing of network software components of nodes of a cluster storage system.BACKGROUND OF THE INVENTION[0003]A storage system typically comprises one or more storage devices into which information may be entered, and from which information may be obtained, as desired. The storage system includes a storage operating system that functionally organizes the system by, inter alia, invoking storage operations in support of a storage service implemented by the system. The storage system may be implemented in accordance with a vari...

AI Technical Summary

Benefits of technology

[0011]In some embodiments, a servicing module residing on each node of the cluster provides less disruptive servicing of the software components of the nodes of a cluster. In these embodiments, each client is configured to retain its client ID and any file handles upon disconnection with a serviced node. Each client is also configured to automatically attempt to reconnect with a partner node and attempt to re-establish the data-access session with the partner node using the retained client ID and file handles. While the clients attempt to reconnect with the partner node, session data (comprising the client IDs and file handles) stored in the serviced node made available to the partner node (e.g., is transferred to the partner node). After the clients have reconnected to the partner node, the clients may use the retained client ID and file handles to continue the data-access session with the partner node. This is possible since the partner node now has access to the session data of the serviced node and thus will recognize and accept the retained client ID and file handles. The partner node may “recognize” the received client IDs and file handles by comparing and matching the received client IDs to the stored client IDs and file handles in the session data of the serviced node.

[0012]In the embodiments described herein, there is less disruption to clients accessing the cluster for data-access sessions during servicing of software components of the nodes of a cluster. In particular, when a serviced node is taken offline and clients are disconnected from the serviced node, the disconnected clients can continue the data-access sessions with the partner node using the previously obtained client IDs and file handles. As such, the client ID does not need to be reproduced through the connection authentication procedure and each file handle does not need to be reproduced through an access request validation procedure.

[0017]The servicing module may then provide access to session data A to the partner network element. For example, the servicing module may transfer session data A (stored in system aggregate A) to system aggregate B for storage. Since the partner network element now has access to session data A, it will recognize the client IDs sent by the clients attempting reconnection and begin accepting the connection attempts based on the received client IDs and session data A. The partner network element may recognize the received client IDs by matching the received client IDs to the stored client IDs in session data A. As such, re-authentication of the client connection and generation of new client IDs may be avoided.

[0019]This process may be repeated for each node in the cluster, whereby each node in the cluster is serviced one after the other. By performing servicing on one node in the cluster at a time, the entire cluster system does not need to be taken offline, thus reducing disruption to client data-access.

Problems solved by technology

If the node does not recognize the client ID and file handle in an access request, the node may deny processing of the access request.

Thus, servicing of the disk element and network element of each node typically causes substantial disruption to client data-access sessions.

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