Storage Controller Using Status Flags for Memory Tiering
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Solution Overview
Problem
Existing data tiering systems face inefficiencies in minimizing data movement between storage tiers, leading to high over-provisioning and rebuild spare costs, especially in higher tiers, and result in increased write amplification and latency due to suboptimal decision-making algorithms.
Innovation Solution
A storage controller that manages data movement between tiers by using flags (Q-flags and F-flags) to track memory chunk status, allowing for efficient data tiering that reduces over-provisioning and rebuild spare costs by moving data to lower tiers, utilizing the time until garbage collection, and enabling burst writes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If data is moved between storage tiers using existing tiering algorithms, then data access efficiency is improved, but data movement frequency increases causing back-and-forth problems
Solution Approach 1:
The patent applies preliminary action by proactively moving data to lower tiers before it is actually needed, based on predictive algorithms that analyze access patterns. This prevents future data movements by ensuring data is already in the optimal location, thereby reducing back-and-forth movements while maintaining fast access efficiency.
2Reliability
If over-provisioning and rebuild spare capacity are increased in higher tiers, then data reliability and rebuild capability are improved, but storage cost increases significantly
Solution Approach 1:
The patent extracts the over-provisioning and rebuild spare capacity requirements from higher-cost tiers and relocates them to lower-cost tiers. By maintaining redundancy information in cheaper storage, the system achieves the same reliability and rebuild capabilities while significantly reducing the expensive capacity reserved in high-performance tiers.
Solution Approach 2:
The patent uses cheaper storage capacity in lower tiers to provide the over-provisioning and rebuild spare functions that were previously reserved in expensive higher tiers. This substitutes expensive permanent reserved capacity with cheaper capacity that can be dynamically allocated, reducing overall storage costs while maintaining reliability.
3Productivity
If garbage collection process is performed frequently to maintain free chunks, then write amplification is reduced, but system latency increases
Solution Approach 1:
The patent implements periodic garbage collection operations scheduled during low-utilization periods rather than continuously or on-demand. This periodic approach allows the system to batch cleanup operations, reducing write amplification through regular maintenance while minimizing latency impact by performing operations when system load is lower.
Solution Approach 2:
The patent introduces an intermediary layer that manages the timing and scheduling of garbage collection operations, acting as a mediator between write operations and the actual cleanup process. This intermediary buffers and coordinates GC activities to smooth out their impact on system latency while maintaining effective reduction of write amplification.
Data Source
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AI summary
Provided is a storage controller for controlling a storage memory. The storage memory includes at least one first tier memory and at least one second tier memory. The first tier memory has a higher access speed than the second tier memory. The storage memory is being arranged to store memory blocks of data grouped in memory chunks associated with an index. A memory chunk indicates the size of a memory operation. The storage controller is configured to determine that a memory chunk is to be moved from the first tier memory to the second tier memory, and write the memory chunk to the second tier rmemory. The storage controller is configured to receive a read request for the memory chunk and in response thereto determine whether the memory chunk is current in the first tier memory, and if so, read the memory chunk from the first tier memory.