RAID Controller SSD Mirroring Wear Distribution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Mirroring using NAND flash SSDs results in simultaneous lifespan expiration of storage devices due to uniform data writing, leading to decreased reliability when data is written and read per page unit and erased per block unit, as existing RAID techniques do not account for varying write sizes and cache management.
Innovation Solution
An information processing apparatus with a controller that writes data to two SSDs differently, where the first SSD receives full data and the second SSD receives data split into page-sized chunks, with intermediate data stored in cache memory, allowing for staggered writing and extended lifespan by managing write operations through a RAID controller card.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the same data is simultaneously written to multiple SSDs in mirroring, then data reliability is improved, but the lifespan of storage devices expires at the same time due to uniform write operations
Solution Approach 1:
The patent segments the write operations by dividing data into different sizes for different SSDs. Specifically, it writes data of a first size to a first SSD and data of a second size (different from the first size) to a second SSD. This segmentation of write operations ensures that wear is distributed unevenly across the storage devices, preventing simultaneous lifespan expiration while maintaining data reliability through mirroring.
2Productivity
If data is written to SSDs per page unit and erased per block unit, then storage efficiency is improved, but uneven distribution of write operations cannot be achieved with conventional RAID techniques
Solution Approach 1:
The patent changes the parameter of write data size to achieve uneven distribution. It explicitly writes data of a first size to a first SSD and data of a second size to a second SSD, where the first size is different from the second size. This parameter change in data size allows the system to adapt to the page-unit write and block-unit erase characteristics of NAND flash SSDs, enabling flexible and uneven distribution of write operations across multiple devices.
Data Source
AI summary
According to one embodiment, an information processing apparatus includes a controller configured to write, first data to a first storage device from a first address to a second address according to a size of the first data, to write second data having a part of the first data to a second storage device from the first address, a size of the second data being equal to n times a page size, to write, to a cache memory, third data which is equal to the first data except the second data, and to write, when the controller receives a writing instruction includes third address being adjacent to the second address and fourth data, fifth data to the second storage device, the fifth data having the third data and at least part of fourth data, and a size of the fifth data is equal to the page size.