Software RAID for Direct-Attached Storage Command Routing
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Solution Overview
Problem
Existing RAID solutions for virtual machines in server devices face issues with high licensing costs, compatibility limitations, and the need for multiple server devices or specialized hardware, particularly when using direct-attached storage devices.
Innovation Solution
A software RAID system that utilizes a software RAID engine to provide a logical storage device to a hypervisor subsystem, presenting a primary controller device and transmitting commands to physical storage devices via controller devices, enabling RAID functionality without dedicated hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vSAN data protection solution is used to protect data on direct-attached storage devices, then data redundancy is achieved, but multiple server devices are required and licensing costs are high
Solution Approach 1:
A software RAID layer is introduced as an intermediary between the hypervisor and physical storage devices. This software RAID controller manages data redundancy and protection for direct-attached storage devices without requiring multiple server devices, thereby resolving the contradiction between achieving data protection and avoiding complex multi-server configurations
2Reliability
If hardware-based RAID data protection solution is implemented, then data redundancy is provided, but hardware costs and device complexity increase
Solution Approach 1:
The patent replaces hardware-based RAID controllers with a software-based RAID implementation. The software RAID engine provides the same data redundancy and protection functionality as hardware RAID but eliminates the need for specialized hardware components, thereby reducing device complexity and hardware costs while maintaining reliability
3Reliability
If VROC data protection solution is used, then RAID1 data protection is provided, but compatibility is limited to specific CPUs and storage devices
Solution Approach 1:
The software RAID implementation is designed to be universally compatible with various CPU architectures and storage device types. Unlike VROC which is limited to specific Intel CPUs and NVMe storage, this software RAID solution can operate with different CPU vendors and multiple storage device types including SAS, SATA, and NVMe, thereby achieving hardware compatibility universality
4Productivity
If software RAID is implemented without presenting controller devices, then system simplicity is maintained, but hypervisor command routing to multiple storage devices is inefficient
Solution Approach 1:
The software RAID controller acts as an intermediary that the hypervisor can interact with using standard RAID commands. This controller then routes commands efficiently to the appropriate physical storage devices, maintaining system simplicity from the hypervisor's perspective while enabling efficient command processing through proper command routing and load distribution across multiple storage devices
Data Source
AI summary
A direct-attached storage device software RAID system includes a chassis housing a software RAID subsystem coupled to physical storage devices, controller devices, and a hypervisor subsystem housed in the chassis. The software RAID subsystem uses the physical storage devices to provide a logical storage device to the hypervisor subsystem. The software RAID subsystem also presents a first controller device to the hypervisor subsystem as a primary controller device that is connected to the logical storage device. When the software RAID subsystem receives a command from the hypervisor subsystem directed to the primary controller device and identifying a logical storage subsystem in the logical storage device, it transmits the command to each of a subset of the physical storage devices that provide the logical storage subsystem in the logical storage device via a respective one of the controller devices that couples the software RAID subsystem to that physical storage device.