Tiered Storage Controller Extent Group Linkage
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Solution Overview
Problem
Tiered storage systems face significant overhead and time-consuming data transfers due to periodic estimation of access frequency, which is inefficient in managing data between high-speed and low-speed storage devices.
Innovation Solution
A storage controller with a tiering controller that dynamically manages data transfer by analyzing access patterns and linkage between logical extents, transferring data from low-speed to high-speed storage based on access frequency and linkage strength, optimizing data placement across tiers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If periodic estimation of access frequency is performed to manage data between storage tiers, then data placement optimization is achieved, but significant overhead and time consumption occur during data transfer
Solution Approach 1:
The system performs preliminary actions by establishing extent groups based on linkage relationships between extents before data transfer is needed. When a data access request is received, the system can immediately identify which extents belong to the same group and transfer them together, avoiding the need for periodic comprehensive estimation and reducing overall transfer time.
Solution Approach 2:
The system uses feedback from access patterns to dynamically adjust data placement. By monitoring access requests and updating linkage relationships in real-time, the system can reorganize extent groups and trigger data transfers between tiers based on actual usage patterns, optimizing placement without requiring lengthy periodic estimations.
2Reliability
If periodic estimation of access frequency is performed to manage data between storage tiers, then data placement optimization is achieved, but significant overhead is generated
Solution Approach 1:
The system segments the storage space into extent groups based on linkage relationships rather than treating all data uniformly. This segmentation allows the system to manage and transfer data in smaller, more manageable groups, reducing the complexity of control operations and avoiding the need for comprehensive periodic estimation of all data.
Solution Approach 2:
By pre-establishing extent groups and their linkage relationships, the system performs preliminary organization of data before access requests arrive. This preliminary action simplifies subsequent control operations, as the system only needs to manage pre-defined groups rather than performing complex periodic analysis of all data.
3Reliability
If data transfer between tiers is performed based on periodical access frequency estimation, then data placement is updated, but a large amount of time is required
Solution Approach 1:
The system performs preliminary organization of data into extent groups based on linkage relationships, so that when data transfer is needed, the system can work with pre-defined groups rather than performing comprehensive reclassification. This preliminary action maintains placement accuracy while significantly reducing transfer time.
Solution Approach 2:
Instead of performing complete periodic estimation and transfer of all data, the system applies partial action by only transferring data from extent groups that have changed their access patterns or linkage relationships. This selective approach maintains sufficient placement accuracy while dramatically improving transfer efficiency.
Data Source
AI summary
According to one embodiment, a tiered storage system includes a first storage device, a second storage device and a storage controller. The first and second storage devices are positioned as an upper tier and a lower tier, respectively. The storage controller transfers data of q physical extents in the second storage device to q free physical extents in the first storage device, when an access request from a host computer designates access to one or more logical blocks including a first logical block, the first logical block is included in a first logical extent, and the first logical extent belongs to an extent group including q logical extents to which the q physical extents are allocated.