LUN Management in SSD Arrays via Non-Contiguous Allocation
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Solution Overview
Problem
Existing solid state disk (SSD) arrays face inefficiencies in managing logical unit numbers (LUNs), particularly in resizing, deletion, or migration, which require formatting the entire memory array, leading to resource consumption and unavailability to other users, especially as capacity grows and the number of users increases.
Innovation Solution
A method for managing LUNs involves identifying affected LUN logical block address (LBA)-groups, assigning them to portions of a storage pool, and maintaining a mapping table to track associations, allowing for non-contiguous allocation and appearance of contiguous storage, thus avoiding the need for re-writing and formatting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If contiguous LBA allocation is used for LUNs, then storage space management is simplified, but resizing or deletion requires formatting the entire memory array which consumes resources and renders SSDs unusable to other users
Solution Approach 1:
The patent segments the storage pool into multiple non-contiguous LBA ranges that can be independently allocated to different LUNs. Instead of requiring a single contiguous block, the system divides storage space into manageable segments that can be freely assigned and reassigned without affecting the entire array, enabling LUN resizing and deletion without global formatting operations.
Solution Approach 2:
The patent introduces a mapping table as an intermediary data structure that translates logical LUN addresses to physical LBA locations in the storage pool. This mapping layer decouples the logical view from the physical storage layout, allowing flexible allocation of non-contiguous LBAs to LUNs while maintaining simple logical addressing, and enabling modifications without disrupting the entire storage system.
2Ease of manufacture
If contiguous LBA allocation is enforced for LUNs, then storage allocation is straightforward, but resizing operations require rewriting and formatting which consumes time and resources
Solution Approach 1:
The patent performs preliminary actions by pre-establishing a mapping table that records the association between LUNs and their allocated LBA ranges before any resizing operation. When resizing is needed, the system simply updates the mapping table entries rather than performing physical rewriting and formatting operations, significantly reducing the time and resources required for LUN resizing.
Solution Approach 2:
The patent uses the mapping table as a logical copy or representation of the actual storage allocation. Instead of modifying the physical storage structure during resizing operations, the system updates the mapping table copy, which then reflects the new allocation. This allows rapid logical changes without time-consuming physical rewriting operations.
3Quantity of substance
If the number of users per SSD increases, then storage capacity utilization improves, but LUN management complexity increases due to formatting requirements
Solution Approach 1:
The patent creates a universal mapping table structure that can accommodate any number of users and LUNs on the SSD array. This single data structure serves multiple functions: tracking allocations, enabling resizing, supporting deletion, and managing non-contiguous LBAs. The same mechanism works regardless of the number of users, eliminating the need for user-specific formatting procedures and reducing management complexity as the system scales.
Data Source
AI summary
A method of managing logical unit numbers (LUNs) in a storage system includes identifying one or more LUN logical block address (LBA)-groups being affected. The one or more LUN LBA-groups defining a LUN. The method further determining the existence of an association of each of the affected LUN LBA-groups to a portion of a storage pool and maintaining a mapping table to track the association of the LUN LBA-groups to the storage pool.