scholarly journals Building Reliable Massive Capacity SSDs through a Flash Aware RAID-Like Protection

2020 ◽  
Vol 10 (24) ◽  
pp. 9149
Author(s):  
Jaeho Kim ◽  
Jung Kyu Park

The demand for mass storage devices has become an inevitable consequence of the explosive increase in data volume. The three-dimensional (3D) vertical NAND (V-NAND) and quad-level cell (QLC) technologies rapidly accelerate the capacity increase of flash memory based storage system, such as SSDs (Solid State Drives). Massive capacity SSDs adopt dozens or hundreds of flash memory chips in order to implement large capacity storage. However, employing such a large number of flash chips increases the error rate in SSDs. A RAID-like technique inside an SSD has been used in a variety of commercial products, along with various studies, in order to protect user data. With the advent of new types of massive storage devices, studies on the design of RAID-like protection techniques for such huge capacity SSDs are important and essential. In this paper, we propose a massive SSD-Aware Parity Logging (mSAPL) scheme that protects against n-failures at the same time in a stripe, where n is protection strength that is specified by the user. The proposed technique allows for us to choose the strength of protection for user data. We implemented mSAPL on a trace-based simulator and evaluated it with real-world I/O workload traces. In addition, we quantitatively analyze the error rates of a flash based SSD for different RAID-like configurations with analytic models. We show that mSAPL outperforms the state-of-the-art RAID-like technique in the performance and reliability.

Electronics ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 847
Author(s):  
Sopanhapich Chum ◽  
Heekwon Park ◽  
Jongmoo Choi

This paper proposes a new resource management scheme that supports SLA (Service-Level Agreement) in a bigdata distributed storage system. Basically, it makes use of two mapping modes, isolated mode and shared mode, in an adaptive manner. In specific, to ensure different QoS (Quality of Service) requirements among clients, it isolates storage devices so that urgent clients are not interfered by normal clients. When there is no urgent client, it switches to the shared mode so that normal clients can access all storage devices, thus achieving full performance. To provide this adaptability effectively, it devises two techniques, called logical cluster and normal inclusion. In addition, this paper explores how to exploit heterogeneous storage devices, HDDs (Hard Disk Drives) and SSDs (Solid State Drives), to support SLA. It examines two use cases and observes that separating data and metadata into different devices gives a positive impact on the performance per cost ratio. Real implementation-based evaluation results show that this proposal can satisfy the requirements of diverse clients and can provide better performance compared with a fixed mapping-based scheme.


2012 ◽  
Vol 566 ◽  
pp. 560-567
Author(s):  
Li Feng Zhou ◽  
Wen Bin Yao ◽  
De Yan Jiang ◽  
Cong Wang

Cloud storage, which is composed of a large number storage devices and servers, provides large-scale flexible storage services through Internet. BCSS (Bupt-Cloud-Storage System) based on some cheap irresponsible PCs is designed as a mass storage platform to offer high reliable and available storage services. Meanwhile, it improves performance of data access by providing support of multi-user concurrent control. The experimental results verify efficiency of storage services and the performance of BCSS.


Author(s):  
Jalil Boukhobza

Data and storage systems are one of the most important issues to tackle when dealing with cloud computing. Performance, in terms of data transfer and energy cost, predictability, and scalability are the main challenges researchers are faced with, and new techniques for storing, managing, and accessing huge amounts of data are required to make cloud computing technology feasible. With the emergence of flash memories in mass storage systems and the advantages it can provide in terms of speed and power efficiency as compared to traditional disks, one must rethink the storage system architectures accordingly. Indeed, the integration of flash memories is considered as a key technology to leverage the performance of data-centric computing. The purpose of this chapter is to introduce flash memory storage systems by focusing on their specific architectures and algorithms, and finally their integration into servers and data centers.


2020 ◽  
Vol 10 (3) ◽  
pp. 747
Author(s):  
Bo-Kyeong Kim ◽  
Gun-Woo Kim ◽  
Dong-Ho Lee

Flash storage devices such as solid-state drives and multimedia cards have been widely used in various applications because of their fast access speed, low power consumption, and high reliability. They consist of NAND flash memories that perform slow block erasures before overwriting data on a prewritten page. This characteristic can lead to performance degradation when applying the original B-tree on the flash storage device without any changes. Although various B-trees have been proposed for flash memory, they still require many flash operations that degrade overall performance. To address the problem, we propose a novel B-tree index structure that reduces the number of write operations and improves the sequential writes by employing cascade memory nodes. The proposed B-tree index structure delays the updates for the modified B-tree nodes and later performs batch writes in a cascade manner. Also, when records with continuous key values are sequentially inserted, the proposed B-tree index structure does not split the leaf node so that it improves write throughput and page utilization. Through mathematical analysis and experimental results, we show that the proposed B-tree index structure always yields better performance than existing techniques.


2015 ◽  
Vol 24 (09) ◽  
pp. 1550128 ◽  
Author(s):  
Bo-Kyeong Kim ◽  
Sang-Won Lee ◽  
Dong-Ho Lee

Flash-based solid state drives (SSDs) have been widely used as storage medium because of their fast access speed, high reliability and low power consumption. In spite of these advantages, they inherit distinct characteristics such as no in-place updates, asymmetric operation speed and unit because they consist of NAND flash memories. Therefore, a disk-based hash index structure may result in severe performance degradation if it is directly deployed on a NAND flash memory-based storage system. In this paper, we propose a new hybrid hash index structure for flash-based SSDs. It delays and reduces the split operations which cause slow block erasure and additional read and write operations by exploiting overflow buckets according to the ratio of updates and deletions. Through various performance evaluations, we show the superiority of our proposed index structure by comparing it to other hash index structures for flash-based SSDs.


2012 ◽  
Vol E95.C (5) ◽  
pp. 837-841 ◽  
Author(s):  
Se Hwan PARK ◽  
Yoon KIM ◽  
Wandong KIM ◽  
Joo Yun SEO ◽  
Hyungjin KIM ◽  
...  

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