Universal Multipath Driver for Storage Failover
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Solution Overview
Problem
Existing multipath drivers for storage systems lack universality, leading to complexity in management, increased costs, reduced reliability, and performance degradation due to the absence of failover, failback, and load balancing capabilities across different storage devices.
Innovation Solution
A universal multipath driver (UMD) that monitors and manages multiple paths to virtual device objects, detecting failures and performing failover and failback operations while balancing load across real physical devices, including external boot devices, by acting as a functional driver for lower-level drivers and maintaining a list of virtual devices for multipath management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple different drivers are installed for different storage device types, then each device type can be managed with dedicated functionality, but system complexity increases and management becomes difficult
Solution Approach 1:
The patent implements a universal multipath driver that can manage multiple types of storage devices (disk drives, tape drives, RAID subsystems, boot devices) through a single driver interface. This driver provides multi-functional capabilities including path monitoring, failover, failback, and load balancing operations across different device types, eliminating the need for separate dedicated drivers for each device type while maintaining device-specific functionality through configurable parameters and device-type-specific operation modes.
2Reliability
If existing multipath drivers are used without failover capability, then system structure is simpler, but system reliability decreases and server downtime increases
Solution Approach 1:
The patent implements preliminary action by pre-configuring multiple redundant paths to storage devices and establishing failover policies before failures occur. The multipath driver continuously monitors path health and maintains backup paths in ready state, so when a failure occurs, the system can immediately switch to an alternate path without interruption to data operations, thereby achieving high reliability without complex real-time decision mechanisms.
Solution Approach 2:
The patent implements feedback mechanisms where the multipath driver continuously monitors the health status of storage paths and device operations. When path failures or device errors are detected, the system automatically adjusts path selection and triggers failover operations. This closed-loop feedback control enables reliable automatic recovery while maintaining manageable system complexity through standardized monitoring and response protocols.
3Productivity
If load balancing is not implemented among storage devices, then system structure is simpler, but performance degrades due to skewed storage utilization
Solution Approach 1:
The patent implements dynamic load balancing where the multipath driver continuously monitors storage device utilization metrics and dynamically adjusts I/O path selection to distribute workload evenly across available paths and devices. The system adapts path selection in real-time based on current device performance and utilization status, preventing any single device from becoming a bottleneck while maintaining simple overall system architecture through centralized driver control.
Data Source
AI summary
An embodiment of the invention is a technique for monitoring via a universal multipath driver (UMD) a first path to one of a plurality of virtual device objects. The virtual device objects are created by the UMD and correspond to a plurality of functional device objects. The functional device objects are created by a plurality of lower level drivers and correspond to a plurality of real physical devices having M device types including an external boot device. The UMD is a functional driver of each of the functional device objects. The lower level drivers control the real physical devices. The UMD detects a failure of the first path to a first virtual device object corresponding to a first real physical device and performs one of failover and failback for the first real physical device.