RAID Storage Controller Dynamic Data Redistribution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In storage devices using RAID configurations with SSDs, uneven free physical capacities among memory units lead to unusable storage capacity, reducing the utilization rate of memory capacities and limiting further data storage when one SSD runs out of space despite others having available capacity.
Innovation Solution
A storage device with a memory controller that associates nonvolatile semiconductor memory chips with logical memory areas, selects semiconductor memory units based on capacity information, and exchanges data entries between units to equalize free physical capacities, ensuring all SSDs in a RAID group can continue to store data by optimizing data distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If data compression is performed within each SSD in a RAID group, then the apparent storage capacity increases and cost per bit decreases, but the free physical capacity becomes uneven among SSDs causing utilization rate to drop
Solution Approach 1:
The storage controller monitors the free physical capacity of each SSD in the RAID group and uses this feedback information to dynamically adjust data distribution. When one SSD's free capacity falls below a threshold, the controller identifies another SSD with excessive free capacity and transfers data between them, ensuring balanced utilization across all devices.
Solution Approach 2:
The system transitions from static data distribution to dynamic adjustment. The storage controller continuously monitors capacity usage and actively redistributes data between SSDs based on real-time conditions, allowing the system to adapt to changing compression rates and maintain optimal utilization.
2Productivity
If striped data storage is used with equal free space requirements, then data can be stored across multiple SSDs, but storage stops when one SSD runs out of space even if others have free capacity
Solution Approach 1:
The storage controller proactively monitors free capacity levels in each SSD and performs data redistribution before any SSD completely runs out of space. By predicting capacity exhaustion and acting in advance, the system prevents storage bottlenecks and ensures continuous operation.
Solution Approach 2:
The storage controller acts as an intermediary between the host system and individual SSDs, managing data distribution independently. It receives write requests, determines optimal destination SSDs based on current capacity levels, and redirects data flow to maintain balanced utilization across the RAID group.
Data Source
AI summary
A storage device comprises plural memory units and a storage controller that controls the memory units as a RAID group. Each memory unit is provided with a nonvolatile semiconductor memory (e.g. flash memory) chip and a memory controller that compresses data and stores the compressed data into the nonvolatile semiconductor memory chips. The memory controller makes a logical memory area available to the storage controller. The storage controller divides the logical memory area into plural entries each of which is a logical memory area of a prescribed size, acquires from respective memory unit capacity information on the data capacity stored into the nonvolatile semiconductor memory, and exchanges data of entries between the semiconductor memory units on the basis of the capacity information.