Cluster Storage Node Servicing via Session Data Copying
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Solution Overview
Problem
The existing methods for servicing network software components in cluster storage systems disrupt client data-access sessions significantly, as they require nodes to be taken offline for maintenance, leading to disconnection and re-authentication of clients.
Innovation Solution
A servicing module that allows clients to retain their client IDs and file handles during disconnection, enabling automatic reconnection to a partner node with access to session data, thus minimizing disruption by avoiding the need for re-authentication and new file handle generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If nodes are taken offline for servicing network software components, then the software can be maintained and updated, but client data-access sessions are disrupted and clients must re-authenticate
Solution Approach 1:
The system divides the cluster into multiple nodes with designated primary and secondary roles. The secondary node can assume the primary node's identity and session data when the primary is offline for servicing, allowing segmentation of servicing operations across different nodes without disrupting overall system availability.
Solution Approach 2:
Session data including client IDs and file handles is copied from the primary node to the secondary node before the primary goes offline. This copying mechanism allows the secondary node to present an identical interface to clients, maintaining session continuity without requiring client re-authentication.
2Ease of repair
If nodes are taken offline for servicing, then software maintenance can be performed, but downtime and loss of productivity occur
Solution Approach 1:
The secondary node is pre-configured with a copy of the primary node's session data before the primary goes offline for maintenance. This preliminary action ensures that when the primary node returns, the secondary can immediately take over without disrupting client access, eliminating downtime and maintaining productivity.
Solution Approach 2:
The system dynamically changes the operational status parameter of nodes, designating one as primary and another as secondary. This parameter change allows flexible assignment of servicing tasks to different nodes while maintaining continuous service availability through the secondary node's ability to assume the primary role.
3Ease of repair
If clients disconnect and reconnect to a different node, then servicing can proceed, but new file handles must be generated and session data lost
Solution Approach 1:
Complete session data including client IDs, file handles, and connection state is copied to the secondary node before the primary goes offline. When clients reconnect, they receive the same file handles and session identifiers, preventing information loss and eliminating the need for re-authentication even though they are connected to a different physical node.
Data Source
AI summary
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.