Virtual RAID Volume Creation with Disk Pool Allocation
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Solution Overview
Problem
Storage virtualization products face challenges in preserving data availability and I/O performance when creating virtual RAID volumes, as backend disk arrays are unaware of the I/O performance and data availability characteristics, leading to suboptimal allocation of physical space in thin-provisioned volumes.
Innovation Solution
A method that exposes backend virtual volumes on physical storage devices, allows selection of RAID levels for desired data availability and I/O performance, and verifies that these volumes are implemented to preserve the selected RAID level characteristics by allocating physical space from different disk pools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the disk array allocates physical space to thin-provisioned volumes from a pool of physical disks without awareness of virtual RAID volume structure, then on-demand allocation is achieved, but data availability and I/O performance characteristics of the virtual RAID volume are compromised
Solution Approach 1:
The patent implements feedback by having the storage virtualization software monitor and communicate the RAID volume structure information back to the disk array. The system tracks which physical disks are allocated to which virtual volumes and uses this information to guide subsequent allocation decisions, ensuring that the disk array becomes aware of the virtual RAID structure and makes informed allocation choices that preserve data availability.
Solution Approach 2:
The storage virtualization software acts as an intermediary between the host system and the disk array. It receives allocation requests, determines the appropriate physical disk based on the virtual RAID structure, and forwards the request to the disk array with the correct allocation target. This intermediary layer ensures that the disk array allocates space in a way that maintains the intended RAID characteristics without requiring the array to understand complex RAID concepts.
2Adaptability or versatility
If the disk array allocates physical space to thin-provisioned volumes without awareness of virtual RAID volume structure, then allocation flexibility is maintained, but I/O performance characteristics of the virtual RAID volume are compromised
Solution Approach 1:
The system uses feedback loops where the storage virtualization software continuously monitors the physical disk allocation status and communicates this information back to the allocation process. When a new volume needs space, the system checks which physical disks are already in use by the same virtual RAID volume and directs allocation to different physical disks, thereby maintaining the striping pattern and optimizing I/O performance.
Solution Approach 2:
The patent applies preliminary action by pre-planning the allocation of physical disks to virtual volumes based on the RAID structure. Before actual data writing occurs, the system determines the optimal physical disk targets for each virtual volume, ensuring that the allocation pattern matches the desired I/O performance characteristics. This proactive approach prevents suboptimal allocation that would occur without advance planning.
3Quantity of substance
If multiple thin-provisioned volumes are allocated from the same physical disk, then storage space utilization is maximized, but the purpose of creating virtual RAID volumes for data availability is defeated
Solution Approach 1:
The system implements feedback by tracking which physical disks are allocated to which virtual volumes and using this information to prevent allocating multiple volumes from the same physical disk. The storage virtualization software maintains an allocation map and checks it before each allocation decision, ensuring that the physical disk distribution matches the virtual RAID structure requirements for data availability.
Solution Approach 2:
The patent applies segmentation by dividing the physical storage resources into distinct segments or pools, each assigned to specific virtual volumes. Instead of treating all physical disks as a single pool, the system segments them based on the virtual RAID structure, ensuring that each virtual volume receives space from appropriate physical disks. This segmentation prevents the concentration of multiple virtual volumes on a single physical disk.
Data Source
AI summary
A method for preserving data availability and I/O performance when creating a virtual RAID volume includes exposing a set of backend virtual volumes. The backend virtual volumes are implemented on a set of physical storage devices (e.g., physical disks or solid state drives) residing on a storage system. The method further enables selection of the set of backend virtual volumes to create a virtual RAID volume having a selected RAID level. The method further provides verification that the backend virtual volumes will be implemented on the physical storage devices in a way that preserves the data availability and I/O performance associated with the selected RAID level.