Dynamic Copy Session State Management for Memory Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Data storage systems face memory constraints as the number of concurrent copy sessions increases, leading to impaired response-time guarantees for reads and writes from hosts due to insufficient available memory.
Innovation Solution
Implementing active and inactive copy-session states in data storage systems, where inactive sessions persist copy-progress data in non-volatile storage, freeing memory and allowing for efficient memory management, and transitioning between states as needed to control memory usage and maintain concurrent copy sessions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of concurrent copy sessions is increased, then the productivity of the data storage system is improved, but the available memory for servicing hosts deteriorates
Solution Approach 1:
The patent implements dynamic memory management by introducing two states for copy sessions: active and inactive. Active copy sessions maintain full memory structures for high-speed copying operations, while inactive copy sessions have their memory structures freed or reduced. The system dynamically transitions copy sessions between these states based on system conditions, allowing the memory footprint to adapt to current workload requirements. This resolves the contradiction by making memory allocation dynamic rather than static, enabling the system to support many copy sessions concurrently while preserving memory for host servicing when needed.
2Speed
If copy sessions are kept in active state to maintain fast copying, then the copying speed is improved, but the memory consumption increases
Solution Approach 1:
The patent applies local quality by differentiating the memory allocation and structure characteristics between active and inactive copy sessions. Active copy sessions receive full memory resources and maintain complete data structures optimized for high-speed copying operations. Inactive copy sessions have their memory structures freed or reduced to minimal necessary allocations. This localized differentiation allows the system to optimize copying speed for active sessions while controlling overall memory consumption through inactive sessions, resolving the contradiction between copying speed and memory consumption.
3Quantity of substance
If memory structures are freed for inactive copy sessions, then the memory availability is improved, but the recovery complexity after crashes increases
Solution Approach 1:
The patent implements preliminary action by maintaining persistent metadata about copy session states and progress information even when memory structures are freed for inactive sessions. This metadata is stored in a manner that enables rapid reconstruction of memory structures upon system recovery. By preparing and preserving this essential information beforehand, the system can quickly restore active copy sessions after crashes or reboots without requiring complex recovery procedures. This resolves the contradiction by making recovery straightforward through pre-prepared state information, while still allowing memory to be freed for inactive sessions.
Data Source
AI summary
A technique for managing copy sessions in a data storage system supports active and inactive copy-session states and reclaims memory for inactive copy sessions to reduce their memory footprints. When a copy session transitions from the active state to the inactive state, the copy session persists certain copy-progress data in non-volatile storage and frees structures in memory previously storing that copy-progress data. The inactive copy session continues to run but performs no copying and consumes less memory. When the copy session later transitions back to the active state, the copy session reads the copy-progress data back into memory and resumes copying.