Storage System Virtual Volume Grouping for Tier Relocation
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Solution Overview
Problem
Existing storage systems face performance issues due to files with high speed requirements being migrated to lower-tier drives with low access frequencies, leading to delayed application responses and suboptimal access performance.
Innovation Solution
Virtual volumes are grouped and relocation conditions are set based on required response performance, including maximum/minimum tier usage, I/O frequency weighting, and targeted average response time, to optimize tier allocation and reduce performance degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If dynamic tiering migrates pages based solely on I/O access frequency, then storage cost is optimized by placing low-access pages on lower-tier drives, but response performance deteriorates when files requiring high speed are incorrectly placed on low-speed drives
Solution Approach 1:
The patent segments the file into two parts: the file header storing metadata including required response performance level, and the file body containing actual data. This segmentation enables the system to distinguish between files with different performance requirements and make appropriate placement decisions for each part, resolving the contradiction between cost optimization and performance reliability.
Solution Approach 2:
The patent applies local quality by assigning different storage tiers to different parts of the file based on their specific requirements. The file header with high I/O frequency is placed on high-speed drives to ensure quick access to metadata, while the file body with lower I/O frequency can be placed on lower-cost, lower-speed drives. This localized differentiation resolves the contradiction by ensuring performance where needed without sacrificing cost optimization elsewhere.
2Reliability
If real data of files requiring high speed response is allocated to upper-tier drives, then response performance is satisfied, but the upper-tier drive capacity is continuously increased leading to higher storage costs
Solution Approach 1:
By segmenting the file into header and body, the system can place only the header (which requires high-speed access due to frequent I/O operations) on upper-tier drives, while placing the larger file body on lower-tier drives. This segmentation prevents unnecessary consumption of expensive upper-tier capacity while maintaining performance for critical operations.
Solution Approach 2:
The patent applies local quality by differentiating storage requirements within the file itself. The header, requiring high-speed access for metadata operations, is placed on high-speed upper-tier drives, while the file body, accessible at lower speeds, is placed on cost-effective lower-tier drives. This resolves the contradiction by optimizing each part according to its specific performance needs rather than placing the entire file uniformly.
3Reliability
If pages are migrated to upper-tier drives to satisfy response performance requirements, then access performance is improved, but the complexity of managing tier allocation increases
Solution Approach 1:
The patent incorporates required response performance level information directly into the file header during file creation or initialization. This preliminary action stores the performance requirement metadata before the file is written to storage, eliminating the need for complex real-time analysis and decision-making during I/O operations. The system simply reads the pre-stored requirement and makes automatic placement decisions, significantly reducing management complexity while maintaining performance.
Data Source
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AI summary
When a plurality of applications operating in a host computer or a storage system uses a same pool, actual data constantly allocated to an upper tier drive satisfying the required response performance will continue to increase. Therefore, when data is migrated by IOPS in page units, the access performance such as the response speed may not be satisfied. Therefore, according to the present invention, multiple virtual volumes used in applications are subjected to grouping. Relocation conditions corresponding to performances required for each group are set in advance, and reallocation of tiers according to the relocation conditions is performed.