Design Challenges On Enterprise Scale Storage Systems Employing Hard Drives And Nand Flash Based Solid State Drives PDF Download
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| Author | : Youngjae Kim |
| Publisher | : |
| Total Pages | : 133 |
| Release | : 2009 |
| Genre | : |
| ISBN | : |
Download Design Challenges on Enterprise-scale Storage Systems Employing Hard Drives and Nand Flash Based Solid-state Drives Book in PDF, ePub and Kindle
Flash memory overcomes some key shortcomings of hard disk drives (HDDs), including faster access to non-sequential data and lower power consumption. Economic forces, driven by the desire to introduce flash into the enterprise market without changing existing software based, have resulted in the emergence of solid state drives (SSDs), flash packaged in HDD from factors and capable of working with device drivers and I/O buses designed for HDDs. Unlike the use of DRAM for caching or buffering, however, certain idiosyncrasies of SSDs make their integration into HDD-based systems non-trivial. Flash memory suffers from limits on its reliability, in an order of magnitude more expensive than the disk, and can be sometimes even slower than the HDD (due to excessive GC induced by high intensity of random writes). Given the complementary properties of HDDs and SDDs in terms of cost, performance, and lifetime, the current consensus among several storage experts is to view SSDs not as a replacement for HDD but rather as a complementary device within the storage hierarchy. In my dissertation, I designed and evaluated such a hybrid system called HybridStore to provide (a) improved capacity planning techniques to administrators with the overall goal of operating within cost-budgets and (b) improved performance/lifetime guarantees during episodes of deviations from expected workloads through several novel mechanisms such as fragmentation busting and write regulation. As an illustrative example of HybridStore's efficacy, a combination of 1 SSD and 6 low-speed, cheaper and higher capacity HDDs is recommended the most cost-effective storage configuration in HybridStore for a predominantly random-write dominant I/O trace from an OLTP application running at a large financial institution. Also, HybridStore employing HDD with small SSD is able to reduce the average response time for Financial trace by about 71% as compared to a HDD-based system. In addition to HybridStore project, I developed a novel design technique of the Flash Translation Layer (FTL) in the SSD. It provides improved performance, reduced garbage collection overhead, and better overloaded behavior compared to state-of- the art FTL schemes. For example, the Financial trace shows a 78% improvement in average response time (due to a 3-fold reduction in operations of the garbage collector), compared to a state-of-the-art FTL scheme. Finally, I also developed and validated flash simulation framework call FlashSim. While a number of well-regarded simulation environments exist for HDDs, the same is not yet true for SSDs. This is due to SSDs having been in the storage market for relatively less time as well as the lack of information (hardware configuration and software methods) about state-of-the-art SSDs that is publicly available. FlashSim aimed at filling this void in performance evaluation of emerging storage systems that employ SSDs.
| Author | : Rino Micheloni |
| Publisher | : Springer |
| Total Pages | : 495 |
| Release | : 2018-07-11 |
| Genre | : Science |
| ISBN | : 9811305994 |
Download Inside Solid State Drives (SSDs) Book in PDF, ePub and Kindle
The revised second edition of this respected text provides a state-of-the-art overview of the main topics relating to solid state drives (SSDs), covering NAND flash memories, memory controllers (including booth hardware and software), I/O interfaces (PCIe/SAS/SATA), reliability, error correction codes (BCH and LDPC), encryption, flash signal processing and hybrid storage. Updated throughout to include all recent work in the field, significant changes for the new edition include: A new chapter on flash memory errors and data recovery procedures in SSDs for reliability and lifetime improvement Updated coverage of SSD Architecture and PCI Express Interfaces moving from PCIe Gen3 to PCIe Gen4 and including a section on NVMe over fabric (NVMf) An additional section on 3D flash memories An update on standard reliability procedures for SSDs Expanded coverage of BCH for SSDs, with a specific section on detection A new section on non-binary Low-Density Parity-Check (LDPC) codes, the most recent advancement in the field A description of randomization in the protection of SSD data against attacks, particularly relevant to 3D architectures The SSD market is booming, with many industries placing a huge effort in this space, spending billions of dollars in R&D and product development. Moreover, flash manufacturers are now moving to 3D architectures, thus enabling an even higher level of storage capacity. This book takes the reader through the fundamentals and brings them up to speed with the most recent developments in the field, and is suitable for advanced students, researchers and engineers alike.
| Author | : Janak R. Koshia |
| Publisher | : |
| Total Pages | : 38 |
| Release | : 2011 |
| Genre | : |
| ISBN | : |
Download Boosting Random Write Performance of Enterprise Flash Storage Systems Book in PDF, ePub and Kindle
NAND flash memory is playing a key role in the revolution of storage systems due to its desirable features such as fast random read and high energy-efficiency. It has been extensively applied in mobile devices like smart phones and PDAs. With increasing capacity, throughput and durability, NAND flash memory based solid state disk (hereafter, flash SSD) has started replacing hard disk drive (HDD) in laptops and desktop systems. Employing high-end flash SSDs in server applications, however, is promising yet challenging. One of the challenges is that currently flash SSD cannot fully meet heavy random write requirements demanded by data-intensive enterprise applications like online transaction processing (OLTP) because of flash memory's inherent update/erasure mechanisms. In this thesis, to boost flash SSD random write performance, we develop a new cache management scheme called element-level parallel optimization (EPO), which buffers and reorders write requests so that element-level parallelism within the architecture of a flash SSD can be mostly utilized. Further, we evaluate the performance of the EPO scheme using a validated disk simulator with both synthetic benchmarks and real-world server-class traces. Experimental results demonstrate that EPO noticeably outperforms traditional least recently used (LRU) and a state-of-the-art flash write buffer management scheme block padding least recently used (BPLRU).
| Author | : |
| Publisher | : |
| Total Pages | : 189 |
| Release | : 2015 |
| Genre | : Electronic books |
| ISBN | : |
Download Boosting Performance and Endurance of Flash-based Storage Systems Book in PDF, ePub and Kindle
NAND flash memory (hereafter, flash memory) has been intensively employed in a wide spectrum of computing systems from mobile devices like smartphones to personal computers to enterprise servers due to its high performance, low power consumption, and shock resistance. However, the further deployment of flash memory is impeded because it also possesses several inherent disadvantages such as limited programming/erase cycles and asymmetrical I/O performance. Besides, the existing frameworks for storage systems are originally designed for block devices (e.g., hard disk drives), which have totally different characteristics from flash memory. In order to utilize flash memory in current storage systems, an extra software layer between a traditional storage system interface and flash memory is needed to mimic the behavior of a block device. Unfortunately, using a flash-based storage system as a traditional HDD noticeably neutralizes the benefits of flash memory.In this dissertation, we holistically examine current flash-based storage systems in different computing platforms ranging from embedded systems to enterprise servers. Firstly, we empirically characterize a representative collection of flash memory devices and then model their raw I/O performance and reliability. Our results demonstrate that flash memory performance and reliability are correlated to programmed data patterns. Further, we propose multiple approaches to improving the performance and reliability of flash-based storage systems at device level. Secondly, we study flash translation layer (FTL) in flash-based solid-state drives (SSDs) for desktops. A plane-centric FTL and a workload-aware MLC/SLC (multi-level cell/single-level cell) partitioning scheme are implemented to boost the performance of a single SSD. Thirdly, the employment of SSD arrays in enterprise servers is investigated. We propose a load-balancing scheme at disk array level to prolong the lifetime of SSD arrays for server applications like OLTP (online transaction processing). Finally, an MTD (memory technology device) array based storage framework will be developed to meet the performance and reliability requirements demanded by emerging and future data-intensive and mission-critical mobile applications.
| Author | : Rino Micheloni |
| Publisher | : Springer |
| Total Pages | : 177 |
| Release | : 2017-03-28 |
| Genre | : Technology & Engineering |
| ISBN | : 331951735X |
Download Solid-State-Drives (SSDs) Modeling Book in PDF, ePub and Kindle
This book introduces simulation tools and strategies for complex systems of solid-state-drives (SSDs) which consist of a flash multi-core microcontroller plus NAND flash memories. It provides a broad overview of the most popular simulation tools, with special focus on open source solutions. VSSIM, NANDFlashSim and DiskSim are benchmarked against performances of real SSDs under different traffic workloads. PROs and CONs of each simulator are analyzed, and it is clearly indicated which kind of answers each of them can give and at a what price. It is explained, that speed and precision do not go hand in hand, and it is important to understand when to simulate what, and with which tool. Being able to simulate SSD’s performances is mandatory to meet time-to-market, together with product cost and quality. Over the last few years the authors developed an advanced simulator named “SSDExplorer” which has been used to evaluate multiple phenomena with great accuracy, from QoS (Quality Of Service) to Read Retry, from LDPC Soft Information to power, from Flash aging to FTL. SSD simulators are also addressed in a broader context in this book, i.e. the analysis of what happens when SSDs are connected to the OS (Operating System) and to the end-user application (for example, a database search). The authors walk the reader through the full simulation flow of a real system-level by combining SSD Explorer with the QEMU virtual platform. The reader will be impressed by the level of know-how and the combination of models that such simulations are asking for.
| Author | : Youngjea Kim |
| Publisher | : |
| Total Pages | : 50 |
| Release | : 2008 |
| Genre | : Computer storage devices |
| ISBN | : |
Download MixedStore Book in PDF, ePub and Kindle
Abstract: "Flash memory overcomes some key shortcomings of HDDs including faster access to non-sequential data (when not degraded by garbage collection (GC) overheads) and lower power consumption. Given the complementary properties of HDDs and Solid State Disks (SSDs) in terms of cost, performance, and lifetime, the current consensus among several storage experts is to view SSD not as a replacement for HDD but rather as a complementary device within the storage hierarchy. Unlike the use of DRAM for caching/buffering, however, certain idiosyncrasies of flash make their integration into HDD-based systems non-trivial. Flash memory suffers from limits on its reliability, is an order of magnitude more expensive than the disk, and can be sometimes even slower than the HDD (due to excessive GC induced by high intensity of random writes). We design and evaluate a simplified hybrid system called MixedStore to provide: (a) improved capacity planning techniques to administrators of such hybrid systems with the overall goal of operating within cost-budgets and (b) improved performance/lifetime guarantees during episodes of deviations from expected workloads through innovative mechanisms such as adaptive wear-leveling, write-regulation and fragmentation busting. We implement a simulator for MixedStore and evaluate its efficacy using a variety of well-regarded enterprise-scale storage traces. As an illustrative example, MixedStore is able to reduce the average system response time by about 71% as compared to a HDD-based system for an enterprise scale random-write dominant Financial Trace. A preliminary investigation of adaptive wear-leveling allows us to extend the useful lifetime of SSD by about 33% in the presence of unanticipated bursts in I/O, thus opening up new challenges in the design of efficient wear-leveling algorithms for the SSD controller."
| Author | : Jian Hu |
| Publisher | : |
| Total Pages | : 140 |
| Release | : 2012 |
| Genre | : Flash memories (Computers) |
| ISBN | : 9781267770226 |
Download Improving Performance of Solid State Drives in Enterprise Environment Book in PDF, ePub and Kindle
Flash memory, in the form of Solid State Drive (SSD), is being increasingly employed in mobile and enterprise-level storage systems due to its superior features such as high energy efficiency, high random read performance and small form factor. However, SSD suffers from the erase-before-write and endurance problems, which limit the direct deployment of SSD in enterprise environment. Existing studies either develop SSD-friendly on-board buffer management algorithms, or design sophisticated Flash Translation Layers (FTL) to ease the erase-before-write problem. This dissertation addresses the two issues and consists of two parts. The first part focuses on the white-box approaches that optimize the internal design of SSD. We design a write buffer management algorithm on top of the log-block FTL, which not only optimizes the write buffer effect by exploiting both the recency and frequency of blocks in the write buffer, but also minimizes the destaging overhead by maximizing the number of valid pages of the destaged block. We further identify that the low garbage collection efficiency problem has a significantly negative impact to the performance of the page-mapped SSD. We design a GC-Aware RAM management algorithm that improves the GC efficiency even if the workloads do not have updating requests by dynamically evaluating the benefits of different destaging policies and adaptively adopting the best one. Moreover, this algorithm minimizes the address translation overhead by exploiting the interplay between the buffer component and the FTL component. The second part focuses on the black-box approaches that optimize the SSD performance externally. As an increasing number of applications deploy SSD in enterprise environment, understanding the performance characteristics of SSD in enterprise environment is becoming critically important. We identify several performance anomalies of SSDs and their performance and endurance impacts on SSD employed in enterprise environment by evaluating several commercial SSDs. Our study provides insights and suggestions to both system developers and SSD vendors. Further, based on the performance anomalies identified, we design an IO scheduler that takes advantage of the SSD features and evaluate its performance on SSD. The scheduler is shown to improve performance in terms of bandwidth and average response time.
| Author | : Rino Micheloni |
| Publisher | : Springer Science & Business Media |
| Total Pages | : 391 |
| Release | : 2012-10-15 |
| Genre | : Science |
| ISBN | : 940075146X |
Download Inside Solid State Drives (SSDs) Book in PDF, ePub and Kindle
Solid State Drives (SSDs) are gaining momentum in enterprise and client applications, replacing Hard Disk Drives (HDDs) by offering higher performance and lower power. In the enterprise, developers of data center server and storage systems have seen CPU performance growing exponentially for the past two decades, while HDD performance has improved linearly for the same period. Additionally, multi-core CPU designs and virtualization have increased randomness of storage I/Os. These trends have shifted performance bottlenecks to enterprise storage systems. Business critical applications such as online transaction processing, financial data processing and database mining are increasingly limited by storage performance. In client applications, small mobile platforms are leaving little room for batteries while demanding long life out of them. Therefore, reducing both idle and active power consumption has become critical. Additionally, client storage systems are in need of significant performance improvement as well as supporting small robust form factors. Ultimately, client systems are optimizing for best performance/power ratio as well as performance/cost ratio. SSDs promise to address both enterprise and client storage requirements by drastically improving performance while at the same time reducing power. Inside Solid State Drives walks the reader through all the main topics related to SSDs: from NAND Flash to memory controller (hardware and software), from I/O interfaces (PCIe/SAS/SATA) to reliability, from error correction codes (BCH and LDPC) to encryption, from Flash signal processing to hybrid storage. We hope you enjoy this tour inside Solid State Drives.
| Author | : Bertrand Dufrasne |
| Publisher | : IBM Redbooks |
| Total Pages | : 72 |
| Release | : 2012-05-10 |
| Genre | : Computers |
| ISBN | : 0738450766 |
Download Solid-State Drive Caching in the IBM XIV Storage System Book in PDF, ePub and Kindle
This IBM® RedpaperTM publication provides information about the implementation and use of solid-state drives (SSDs) in IBM XIV® Storage System XIV Generation 3 (Gen3), running XIV software version 11.1.0 or later. In the XIV system, SSDs are used to increase the read cache capacity of the existing DRAM memory cache, and are not used for persistent storage. This paper begins with a high-level overview of the SSD implementation in XIV and a brief review of the SSD technology, with focus on the XIV system. It explains the SSD Caching design and implementation in XIV. Then it examines typical workloads that can benefit from the SSD Caching extension and introduces the tools and utilities to help you analyze and understand the workload. In particular, it highlights the block tracing facility that was designed and developed by IBM Research. Then this paper explains the process that authorized IBM services representatives use to install SSD Caching. It reviews the changes made to the XIV GUI and the XCLI to support SSD Caching. Finally this paper provides a listing of the new alert-generating events and monitoring options that are provided for SSD support. This paper is intended for users who want an insight into the XIV SSD Caching implementation and architecture, its capabilities, and usage. For more information about the IBM XIV Storage System, see the IBM Redbooks® publication, "IBM XIV Storage System: Architecture, Implementation, and Usage," SG24-7659.
| Author | : Guanying Wu |
| Publisher | : |
| Total Pages | : 106 |
| Release | : 2013 |
| Genre | : Information retrieval |
| ISBN | : |
Download Performance and Reliability Study and Exploration of NAND Flash-based Solid State Drives Book in PDF, ePub and Kindle
The research that stems from my doctoral dissertation focuses on addressing essential challenges in developing techniques that utilize solid-state memory technologies (with emphasis on NAND flash memory) from device, circuit, architecture, and system perspectives in order to exploit their true potential for improving I/O performance in high-performance computing systems. These challenges include not only the performance quirks arising from the physical nature of NAND flash memory, e.g., the inability to modify data in-place, read/write performance asymmetry, and slow and constrained erase functionality, but also the reliability drawbacks that limits solid state drives (SSDs) from widely deployed. To address these challenges, I have proposed, analyzed, and evaluated the I/O scheduling schemes, strategies for storage space virtualization, and data protection methods, to boost the performance and reliability of SSDs.
