Theoretical Aspects of Storage Systems Autumn 2009

Size: px
Start display at page:

Download "Theoretical Aspects of Storage Systems Autumn 2009"

Transcription

1 Theoretical Aspects of Storage Systems Autumn 2009 Chapter 2: Double Disk Failures André Brinkmann

2 Data Corruption in the Storage Stack What are Latent Sector Errors What is Silent Data Corruption Checksum Mismatches Identity Discrepancies and Parity Inconsistencies Experiences concerning Silent Data Corruption How to detect these errors and how do they occur Are there any differences between nearline disks and enterprise class disks Is the age of a disk significant Is there any temporal / spatial locality Is the block number important What are the influences of silent data corruption and latent sector errors on RAID recovery?

3 Outline Importance of multi-error correcting codes RAID 6 strategies Reed-Solomon Codes and Galois fields RAID with Double Parity-Encodings Disk Arrays Row Diagonal Parity EVENODD

4 Double Disk Failures Assumptions for storage cluster environment: 1 PByte of data stored on 2000 computers Environment is grouped into 200 RAID 5 sets with 10 disks each MTBF of each computer (including disks) is 1000 days Recovery of a computer is 1 day MTTDL= d ( ) d 55d Protection against single disk failures not enough in large scale environments RAID 6 is mandatory in large environments Recovery time has to be minimized Example taken from Lustre Manual v1.6, August 2007

5 RAID 6 Any form of RAID that can continue to execute read and write requests to all of an array s virtual disks in the presence of two concurrent disk failures. Both dual check data computations (parity and Reed-Solomon) and orthogonal dual parity have been proposed for RAID Level 6. SNIA: The Dictionary if Storage Networking Terminology Coding / Implementation is not standardized

6 Terms and Definitions Number of data disks: n Number of coding disks: m Rate of a code: R = n/(n+m) Identifiable Failure: Erasure

7 Issues with Erasure Coding Failure Coverage - Four ways to specify Specified by a threshold: (e.g. 3 erasures always tolerated) Specified by an average: (e.g. can recover from an average of erasures). Specified as MDS (Maximum Distance Separable): MDS: Threshold = average = m. Space optimal. Specified by Overhead Factor f: f = factor from MDS = m/average. f is always >= 1 f = 1 is MDS. J. Plank: Erasure Codes for Storage Applications.Tutorial given at FAST-2005

8 Problem Definition Partitioning of (n+m) disks into n data disks d i,,d n and m checksum devices c 1,, c m Every disk can store k Bytes Aim: Up to m disks can fail without data loss Capacity of each disk is given in chunks of the size of a words l = ( k Bytes) 8 bits 1 word = 8k byte w bits w Encoding function F i for chunk j on checksum disk i is only based on corresponding words on data disks c i, j = F i (d 1, j,d 2, j,,d n, j ) Update from data word d j to d j on disk x only requires an update for the checksums of the same row ' c i, j ' = G i (d x, j,d x, j,c i, j ) J. Plank: A Tutorial on Reed-Solomon Coding for Fault-Tolerant RAID-like Systems

9 RAID 5 properties For RAID 5, the number of checksum devices is m=1 and word length is w=1 The checksum is computed as follows: c 1 = F 1 (d 1,,d n ) = d 1 d 2 d n c can be recalculated from the parity of its old value and the old and new data word c 1 ' ' ' = G 1, j (d j,d j,c 1 ) = c 1 d j d j Each word of a failed device can be restored as the parity of the corresponding words on the remaining devices: d j = d 1 d j 1 d j +1 d n c 1 J. Plank: A Tutorial on Reed-Solomon Coding for Fault-Tolerant RAID-like Systems

10 Reed-Solomon Codes The only MDS coding technique for arbitrary n and m This means that m erasures are always tolerated Have been around for decades Operate on binary words of data, composed of w bits, where 2 w n+m Expensive J. Plank: Erasure Codes for Storage Applications.Tutorial given at FAST-2005

11 Multi-error correcting Reed-Solomon codes Standard approach for disk protection Use matrices A,E with and the following properties: The system stays linearly independent after the elimination of m rows in A or E Data can be reconstructed using the Gaussian elimination method Derive from a Vandermonde Matrix J. Plank: A Tutorial on Reed-Solomon Coding for Fault-Tolerant RAID-like Systems

12 Challenges of Reed-Solomon Codes It has to hold that 2 w > n + m Word size is an issue: If n+m 256, we can use bytes as words. If n+m 65,536, we can use shorts as words Arithmetic has to be closed under addition and multiplication (and has to contain the corresponding inverse) Holds without problems for infinite precision real numbers, but not for fixed sized words or even integers Frequent Error: calculate using integer modulo 2 w Division not defined for all elements elimination method is not possible Use Galois Fields with 2 w elements GF(2 w ) J. Plank: A Tutorial on Reed-Solomon Coding for Fault-Tolerant RAID-like Systems

13 Galois Field Arithmetic GF(2 w ) has elements 0, 1, 2,, 2 w -1 Addition = XOR Easy to implement Nice and Fast Multiplication hard to explain If w small ( 8), use multiplication table If w bigger ( 16), use log/anti-log tables Otherwise, use an iterative process J. Plank: Erasure Codes for Storage Applications.Tutorial given at FAST-2005

14 Orthogonal Parity RAID Disks are organized as a 2-dimensional matrix Parity is computed for Each row Each column Advantages Allows failure of many (at least 2) disks Disadvantages More parity blocks needed Slow writes: Each write requires 3 read and 4 write operations Each block represents a dedicated disk Single disk failure handled similar to RAID All double disk failures can be handled by row and/or column Parity

15 Row-Diagonal Parity (RDP) RAID Dedicated RAID Double Parity implementation from NetApp Reduces number of necessary parity disks at the cost that not every failure can be directly resolved First parity dimension is performed as RAID 5 over each row and -parities are calculated for each stripe Stripe consits of p disk with p is prime number and disks 0 p-1 include parity disks Data blocks are stored in disks 0 p 2 Block (i,k) belongs to parity set (i+k) mod p First or last diagonal cannot be used to build own parity DP DP DP DP Corbet et. al: Row-Diagonal Parity for Double Disk Failure Correction, FAST 2004

16 Erasures and RDP Possible cases: Only a single disk fails: No difference compared to RAID 4 Two disks fail: Block (0,1) can be restored based on a diagonal Block (0,0) can be reconstructed AFTERWARDS based on a stripe Block (3,0) will be restored based on a diagonal... DP DP DP DP

17 RDP and Parity distribution Original layout of RDP has same bottleneck as RAID 4 A rotation of the parity disk after each stripe seems at least difficult If RDP pattern consists of m rows then it is possible to rotate the meaning of the disks every m rows m m

18 EVENODD EVENODD has been proposed in 1994 First MDS code, which has been soley based on parities and which corrects two erasures Can be seen as foundation of RDP Higher number of operations for update and reconstruction as RDP Every storage node forms one column Number of data nodes: m with m is prime Number of nodes: m + 2 Blaum, Bradey et. al: EvenOdd An optimal scheme for tolerating double disk Failures in RAID architectures

19 EVENODD Codes Definition of the blocks as matrix of dimension (m-1) x (m+1) with elements a i,j Element a i,j with 0 < i < m-2 and 0 < j < m is symbol j on disk I Disks m and m+1 store redundant information Imaginary Zero-row a m-1,j as last row Calculation of stripe parities: Calculation of diagonal parities:

20 EVENODD Codes parity I parity II adjuster Parity node1: Simple horizontal parity Parity node 2: Diagonal parity including additional adjuster Slides is based on: Huang, Xu:Star an Efficient Encoding Scheme for Correcting Triple Storage Node Failures, Fast 2005

21 Evenodd Decoding Note that S is parity of second parity column There will be at least one diagonal that is missing just one data word. Decode it / them Then there will be at least one row missing just one data word: Decode it / them Continue this process until all the data words are decoded J. Plank: Erasure Codes for Storage Applications.Tutorial given at FAST-2005

22 STAR: 3-error correcting code Extention of EVENODD Additional parity row parity III Folie von: Huang, Xu:Star an Efficient Encoding Scheme for Correcting Triple Storage Node Failures, Fast 2005

23 Decoding Complexity Comparison between Star, Evenodd, an additional codes from Blaum, and a purely XOR-basierten RS-Code from Blömer et al. Slide based on Huang, Xu:Star an Efficient Encoding Scheme for Correcting Triple Storage Node Failures, Fast 2005

24 Slide based on Huang, Xu:Star an Efficient Encoding Scheme for Correcting Triple Storage Node Failures, Fast 2005 Decoding Performance

Distributed Storage Networks and Computer Forensics

Distributed Storage Networks and Computer Forensics Distributed Storage Networks 5 Raid-6 Encoding Technical Faculty Winter Semester 2011/12 RAID Redundant Array of Independent Disks Patterson, Gibson, Katz, A Case for Redundant Array of Inexpensive Disks,

More information

Algorithms and Methods for Distributed Storage Networks 5 Raid-6 Encoding Christian Schindelhauer

Algorithms and Methods for Distributed Storage Networks 5 Raid-6 Encoding Christian Schindelhauer Algorithms and Methods for Distributed Storage Networks 5 Raid-6 Encoding Institut für Informatik Wintersemester 2007/08 RAID Redundant Array of Independent Disks Patterson, Gibson, Katz, A Case for Redundant

More information

STAR : An Efficient Coding Scheme for Correcting Triple Storage Node Failures

STAR : An Efficient Coding Scheme for Correcting Triple Storage Node Failures STAR : An Efficient Coding Scheme for Correcting Triple Storage Node Failures Cheng Huang, Member, IEEE, and Lihao Xu, Senior Member, IEEE Abstract Proper data placement schemes based on erasure correcting

More information

Theoretical Aspects of Storage Systems Autumn 2009

Theoretical Aspects of Storage Systems Autumn 2009 Theoretical Aspects of Storage Systems Autumn 2009 Chapter 1: RAID André Brinkmann University of Paderborn Personnel Students: ~13.500 students Professors: ~230 Other staff: ~600 scientific, ~630 non-scientific

More information

Reliability and Fault Tolerance in Storage

Reliability and Fault Tolerance in Storage Reliability and Fault Tolerance in Storage Dalit Naor/ Dima Sotnikov IBM Haifa Research Storage Systems 1 Advanced Topics on Storage Systems - Spring 2014, Tel-Aviv University http://www.eng.tau.ac.il/semcom

More information

A Tutorial on Reed-Solomon Coding for Fault-Tolerance in RAID-like Systems

A Tutorial on Reed-Solomon Coding for Fault-Tolerance in RAID-like Systems A Tutorial on Reed-Solomon Coding for Fault-Tolerance in RAID-like Systems James S Plank Department of Computer Science University of Tennessee February 19, 1999 Abstract It is well-known that Reed-Solomon

More information

Towards High Security and Fault Tolerant Dispersed Storage System with Optimized Information Dispersal Algorithm

Towards High Security and Fault Tolerant Dispersed Storage System with Optimized Information Dispersal Algorithm Towards High Security and Fault Tolerant Dispersed Storage System with Optimized Information Dispersal Algorithm I Hrishikesh Lahkar, II Manjunath C R I,II Jain University, School of Engineering and Technology,

More information

RAID Triple Parity. Peter Corbett. Atul Goel ABSTRACT. Categories and Subject Descriptors. General Terms. Keywords

RAID Triple Parity. Peter Corbett. Atul Goel ABSTRACT. Categories and Subject Descriptors. General Terms. Keywords RAID Triple Parity Atul Goel NetApp Inc atul.goel@netapp.com Peter Corbett NetApp Inc peter.corbett@netapp.com ABSTRACT RAID triple parity (RTP) is a new algorithm for protecting against three-disk failures.

More information

EMC CLARiiON RAID 6 Technology A Detailed Review

EMC CLARiiON RAID 6 Technology A Detailed Review A Detailed Review Abstract This white paper discusses the EMC CLARiiON RAID 6 implementation available in FLARE 26 and later, including an overview of RAID 6 and the CLARiiON-specific implementation, when

More information

A Reed-Solomon Code for Disk Storage, and Efficient Recovery Computations for Erasure-Coded Disk Storage

A Reed-Solomon Code for Disk Storage, and Efficient Recovery Computations for Erasure-Coded Disk Storage A Reed-Solomon Code for Disk Storage, and Efficient Recovery Computations for Erasure-Coded Disk Storage M. S. MANASSE Microsoft Research, Mountain View, California, USA C. A. THEKKATH Microsoft Research,

More information

Data Storage - II: Efficient Usage & Errors

Data Storage - II: Efficient Usage & Errors Data Storage - II: Efficient Usage & Errors Week 10, Spring 2005 Updated by M. Naci Akkøk, 27.02.2004, 03.03.2005 based upon slides by Pål Halvorsen, 12.3.2002. Contains slides from: Hector Garcia-Molina

More information

A Piggybacking Design Framework for Read-and Download-efficient Distributed Storage Codes

A Piggybacking Design Framework for Read-and Download-efficient Distributed Storage Codes A Piggybacing Design Framewor for Read-and Download-efficient Distributed Storage Codes K V Rashmi, Nihar B Shah, Kannan Ramchandran, Fellow, IEEE Department of Electrical Engineering and Computer Sciences

More information

Christian Schindelhauer Technical Faculty Computer-Networks and Telematics University of Freiburg

Christian Schindelhauer Technical Faculty Computer-Networks and Telematics University of Freiburg DAAD Summerschool Curitiba 2011 Aspects of Large Scale High Speed Computing Building Blocks of a Cloud Storage Networks 2: Virtualization of Storage: RAID, SAN and Virtualization Christian Schindelhauer

More information

Linear Codes. Chapter 3. 3.1 Basics

Linear Codes. Chapter 3. 3.1 Basics Chapter 3 Linear Codes In order to define codes that we can encode and decode efficiently, we add more structure to the codespace. We shall be mainly interested in linear codes. A linear code of length

More information

An Analysis of Data Corruption in the Storage Stack

An Analysis of Data Corruption in the Storage Stack Department of Computer Science, Institute for System Architecture, Operating Systems Group An Analysis of Data Corruption in the Storage Stack Lakshmi N. Bairavasundaram, Garth Goodson, Bianca Schroeder,

More information

The mathematics of RAID-6

The mathematics of RAID-6 The mathematics of RAID-6 H. Peter Anvin First version 20 January 2004 Last updated 20 December 2011 RAID-6 supports losing any two drives. syndromes, generally referred P and Q. The way

More information

The mathematics of RAID-6

The mathematics of RAID-6 The mathematics of RAID-6 H. Peter Anvin 1 December 2004 RAID-6 supports losing any two drives. The way this is done is by computing two syndromes, generally referred P and Q. 1 A quick

More information

Why disk arrays? CPUs speeds increase faster than disks. - Time won t really help workloads where disk in bottleneck

Why disk arrays? CPUs speeds increase faster than disks. - Time won t really help workloads where disk in bottleneck 1/19 Why disk arrays? CPUs speeds increase faster than disks - Time won t really help workloads where disk in bottleneck Some applications (audio/video) require big files Disk arrays - make one logical

More information

A Cost-based Heterogeneous Recovery Scheme for Distributed Storage Systems with RAID-6 Codes

A Cost-based Heterogeneous Recovery Scheme for Distributed Storage Systems with RAID-6 Codes A Cost-based Heterogeneous Recovery Scheme for Distributed Storage Systems with RAID-6 Codes Yunfeng Zhu, Patrick P. C. Lee, Liping Xiang, Yinlong Xu, Lingling Gao School of Computer Science and Technology,

More information

RAID. Tiffany Yu-Han Chen. # The performance of different RAID levels # read/write/reliability (fault-tolerant)/overhead

RAID. Tiffany Yu-Han Chen. # The performance of different RAID levels # read/write/reliability (fault-tolerant)/overhead RAID # The performance of different RAID levels # read/write/reliability (fault-tolerant)/overhead Tiffany Yu-Han Chen (These slides modified from Hao-Hua Chu National Taiwan University) RAID 0 - Striping

More information

AN INTRODUCTION TO ERROR CORRECTING CODES Part 1

AN INTRODUCTION TO ERROR CORRECTING CODES Part 1 AN INTRODUCTION TO ERROR CORRECTING CODES Part 1 Jack Keil Wolf ECE 154C Spring 2008 Noisy Communications Noise in a communications channel can cause errors in the transmission of binary digits. Transmit:

More information

Definition of RAID Levels

Definition of RAID Levels RAID The basic idea of RAID (Redundant Array of Independent Disks) is to combine multiple inexpensive disk drives into an array of disk drives to obtain performance, capacity and reliability that exceeds

More information

RAID. Storage-centric computing, cloud computing. Benefits:

RAID. Storage-centric computing, cloud computing. Benefits: RAID Storage-centric computing, cloud computing. Benefits: Improved reliability (via error correcting code, redundancy). Improved performance (via redundancy). Independent disks. RAID Level 0 Provides

More information

Practical Data Integrity Protection in Network-Coded Cloud Storage

Practical Data Integrity Protection in Network-Coded Cloud Storage Practical Data Integrity Protection in Network-Coded Cloud Storage Henry C. H. Chen Department of Computer Science and Engineering The Chinese University of Hong Kong Outline Introduction FMSR in NCCloud

More information

Storing Data: Disks and Files

Storing Data: Disks and Files Storing Data: Disks and Files (From Chapter 9 of textbook) Storing and Retrieving Data Database Management Systems need to: Store large volumes of data Store data reliably (so that data is not lost!) Retrieve

More information

Using RAID6 for Advanced Data Protection

Using RAID6 for Advanced Data Protection Using RAI6 for Advanced ata Protection 2006 Infortrend Corporation. All rights reserved. Table of Contents The Challenge of Fault Tolerance... 3 A Compelling Technology: RAI6... 3 Parity... 4 Why Use RAI6...

More information

RAID Overview 91.520

RAID Overview 91.520 RAID Overview 91.520 1 The Motivation for RAID Computing speeds double every 3 years Disk speeds can t keep up Data needs higher MTBF than any component in system IO Performance and Availability Issues!

More information

Surviving Two Disk Failures. Introducing Various RAID 6 Implementations

Surviving Two Disk Failures. Introducing Various RAID 6 Implementations Surviving Two Failures Introducing Various RAID 6 Implementations Notices The information in this document is subject to change without notice. While every effort has been made to ensure that all information

More information

RAID-DP: NetApp Implementation of Double- Parity RAID for Data Protection

RAID-DP: NetApp Implementation of Double- Parity RAID for Data Protection Technical Report RAID-DP: NetApp Implementation of Double- Parity RAID for Data Protection Jay White & Chris Lueth, NetApp May 2010 TR-3298 ABSTRACT This document provides an in-depth overview of the NetApp

More information

Data Protection Technologies: What comes after RAID? Vladimir Sapunenko, INFN-CNAF HEPiX Spring 2012 Workshop

Data Protection Technologies: What comes after RAID? Vladimir Sapunenko, INFN-CNAF HEPiX Spring 2012 Workshop Data Protection Technologies: What comes after RAID? Vladimir Sapunenko, INFN-CNAF HEPiX Spring 2012 Workshop Arguments to be discussed Scaling storage for clouds Is RAID dead? Erasure coding as RAID replacement

More information

COMP 7970 Storage Systems

COMP 7970 Storage Systems COMP 797 Storage Systems Dr. Xiao Qin Department of Computer Science and Software Engineering Auburn University http://www.eng.auburn.edu/~xqin xqin@auburn.edu COMP 797, Auburn University Slide 3b- Problems

More information

RAID Level Descriptions. RAID 0 (Striping)

RAID Level Descriptions. RAID 0 (Striping) RAID Level Descriptions RAID 0 (Striping) Offers low cost and maximum performance, but offers no fault tolerance; a single disk failure results in TOTAL data loss. Businesses use RAID 0 mainly for tasks

More information

Rethinking Erasure Codes for Cloud File Systems: Minimizing I/O for Recovery and Degraded Reads

Rethinking Erasure Codes for Cloud File Systems: Minimizing I/O for Recovery and Degraded Reads Rethinking Erasure Codes for Cloud File Systems: Minimizing I/O for Recovery and Degraded Reads Osama Khan, Randal Burns Department of Computer Science Johns Hopkins University James Plank, William Pierce

More information

A Tutorial on Reed-Solomon Coding for Fault-Tolerance in RAID-like Systems

A Tutorial on Reed-Solomon Coding for Fault-Tolerance in RAID-like Systems A Tutorial on Reed-olomon Coding for Fault-Tolerance in RAID-like ystems James lank Technical Report C-96-332 Department of Computer cience University of Tennessee IMORTANT The information dispersal matrix

More information

RAID-DP : NETWORK APPLIANCE IMPLEMENTATION OF RAID DOUBLE PARITY FOR DATA PROTECTION A HIGH-SPEED IMPLEMENTATION OF RAID 6

RAID-DP : NETWORK APPLIANCE IMPLEMENTATION OF RAID DOUBLE PARITY FOR DATA PROTECTION A HIGH-SPEED IMPLEMENTATION OF RAID 6 RAID-DP : NETWORK APPLIANCE IMPLEMENTATION OF RAID DOUBLE PARITY FOR DATA PROTECTION A HIGH-SPEED IMPLEMENTATION OF RAID 6 Chris Lueth, Network Appliance, Inc. TR-3298 [12/2006] ABSTRACT To date, RAID

More information

200 Chapter 7. (This observation is reinforced and elaborated in Exercises 7.5 and 7.6, and the reader is urged to work through them.

200 Chapter 7. (This observation is reinforced and elaborated in Exercises 7.5 and 7.6, and the reader is urged to work through them. 200 Chapter 7 (This observation is reinforced and elaborated in Exercises 7.5 and 7.6, and the reader is urged to work through them.) 7.2 RAID Disks are potential bottlenecks for system performance and

More information

Why disk arrays? CPUs improving faster than disks

Why disk arrays? CPUs improving faster than disks Why disk arrays? CPUs improving faster than disks - disks will increasingly be bottleneck New applications (audio/video) require big files (motivation for XFS) Disk arrays - make one logical disk out of

More information

Magnus: Peer to Peer Backup System

Magnus: Peer to Peer Backup System Magnus: Peer to Peer Backup System Naveen Gattu, Richard Huang, John Lynn, Huaxia Xia Department of Computer Science University of California, San Diego Abstract Magnus is a peer-to-peer backup system

More information

Disk Array Data Organizations and RAID

Disk Array Data Organizations and RAID Guest Lecture for 15-440 Disk Array Data Organizations and RAID October 2010, Greg Ganger 1 Plan for today Why have multiple disks? Storage capacity, performance capacity, reliability Load distribution

More information

Chapter 13 File and Database Systems

Chapter 13 File and Database Systems Chapter 13 File and Database Systems Outline 13.1 Introduction 13.2 Data Hierarchy 13.3 Files 13.4 File Systems 13.4.1 Directories 13.4. Metadata 13.4. Mounting 13.5 File Organization 13.6 File Allocation

More information

Chapter 13 File and Database Systems

Chapter 13 File and Database Systems Chapter 13 File and Database Systems Outline 13.1 Introduction 13.2 Data Hierarchy 13.3 Files 13.4 File Systems 13.4.1 Directories 13.4. Metadata 13.4. Mounting 13.5 File Organization 13.6 File Allocation

More information

HDP Code: A Horizontal-Diagonal Parity Code to Optimize I/O Load Balancing in RAID-6

HDP Code: A Horizontal-Diagonal Parity Code to Optimize I/O Load Balancing in RAID-6 HDP Code: A Horizontal-Diagonal Parity Code to Optimize I/O Load Balancing in RAID-6 Chentao Wu, Xubin He, Guanying Wu Shenggang Wan, Xiaohua Liu, Qiang Cao, Changsheng Xie Department of Electrical & Computer

More information

Big Data & Scripting storage networks and distributed file systems

Big Data & Scripting storage networks and distributed file systems Big Data & Scripting storage networks and distributed file systems 1, 2, in the remainder we use networks of computing nodes to enable computations on even larger datasets for a computation, each node

More information

Today s Papers. RAID Basics (Two optional papers) Array Reliability. EECS 262a Advanced Topics in Computer Systems Lecture 4

Today s Papers. RAID Basics (Two optional papers) Array Reliability. EECS 262a Advanced Topics in Computer Systems Lecture 4 EECS 262a Advanced Topics in Computer Systems Lecture 4 Filesystems (Con t) September 15 th, 2014 John Kubiatowicz Electrical Engineering and Computer Sciences University of California, Berkeley Today

More information

A Performance Comparison of Open-Source Erasure Coding Libraries for Storage Applications

A Performance Comparison of Open-Source Erasure Coding Libraries for Storage Applications A Performance Comparison of Open-Source Erasure Coding Libraries for Storage Applications Catherine D. Schuman James S. Plank Technical Report UT-CS-8-625 Department of Electrical Engineering and Computer

More information

IBM System x GPFS Storage Server

IBM System x GPFS Storage Server IBM System x GPFS Storage Server Schöne Aussicht en für HPC Speicher ZKI-Arbeitskreis Paderborn, 15.03.2013 Karsten Kutzer Client Technical Architect Technical Computing IBM Systems & Technology Group

More information

COSC 6374 Parallel Computation. Parallel I/O (I) I/O basics. Concept of a clusters

COSC 6374 Parallel Computation. Parallel I/O (I) I/O basics. Concept of a clusters COSC 6374 Parallel I/O (I) I/O basics Fall 2012 Concept of a clusters Processor 1 local disks Compute node message passing network administrative network Memory Processor 2 Network card 1 Network card

More information

Reliability of Data Storage Systems

Reliability of Data Storage Systems Zurich Research Laboratory Ilias Iliadis April 2, 25 Keynote NexComm 25 www.zurich.ibm.com 25 IBM Corporation Long-term Storage of Increasing Amount of Information An increasing amount of information is

More information

Efficient LDPC Code Based Secret Sharing Schemes and Private Data Storage in Cloud without Encryption

Efficient LDPC Code Based Secret Sharing Schemes and Private Data Storage in Cloud without Encryption Efficient LDPC Code Based Secret Sharing Schemes and Private Data Storage in Cloud without Encryption Yongge Wang Department of SIS, UNC Charlotte, USA yonwang@uncc.edu Abstract. LDPC codes, LT codes,

More information

A Hitchhiker s Guide to Fast and Efficient Data Reconstruction in Erasure-coded Data Centers

A Hitchhiker s Guide to Fast and Efficient Data Reconstruction in Erasure-coded Data Centers A Hitchhiker s Guide to Fast and Efficient Data Reconstruction in Erasure-coded Data Centers K V Rashmi 1, Nihar B Shah 1, Dikang Gu 2, Hairong Kuang 2, Dhruba Borthakur 2, and Kannan Ramchandran 1 ABSTRACT

More information

Non-Redundant (RAID Level 0)

Non-Redundant (RAID Level 0) There are many types of RAID and some of the important ones are introduced below: Non-Redundant (RAID Level 0) A non-redundant disk array, or RAID level 0, has the lowest cost of any RAID organization

More information

Fault Tolerance & Reliability CDA 5140. Chapter 3 RAID & Sample Commercial FT Systems

Fault Tolerance & Reliability CDA 5140. Chapter 3 RAID & Sample Commercial FT Systems Fault Tolerance & Reliability CDA 5140 Chapter 3 RAID & Sample Commercial FT Systems - basic concept in these, as with codes, is redundancy to allow system to continue operation even if some components

More information

ES-1 Elettronica dei Sistemi 1 Computer Architecture

ES-1 Elettronica dei Sistemi 1 Computer Architecture ES- Elettronica dei Sistemi Computer Architecture Lesson 7 Disk Arrays Network Attached Storage 4"» "» 8"» 525"» 35"» 25"» 8"» 3"» high bandwidth disk systems based on arrays of disks Decreasing Disk Diameters

More information

CS 61C: Great Ideas in Computer Architecture. Dependability: Parity, RAID, ECC

CS 61C: Great Ideas in Computer Architecture. Dependability: Parity, RAID, ECC CS 61C: Great Ideas in Computer Architecture Dependability: Parity, RAID, ECC Instructor: Justin Hsia 8/08/2013 Summer 2013 Lecture #27 1 Review of Last Lecture MapReduce Data Level Parallelism Framework

More information

Exercise 2 : checksums, RAID and erasure coding

Exercise 2 : checksums, RAID and erasure coding Exercise 2 : checksums, RAID and erasure coding Sébastien Ponce May 22, 2015 1 Goals of the exercise Play with checksums and compare efficiency and robustness Use hand written version of RAID systems and

More information

High Performance Computing. Course Notes 2007-2008. High Performance Storage

High Performance Computing. Course Notes 2007-2008. High Performance Storage High Performance Computing Course Notes 2007-2008 2008 High Performance Storage Storage devices Primary storage: register (1 CPU cycle, a few ns) Cache (10-200 cycles, 0.02-0.5us) Main memory Local main

More information

Cryptography and Network Security. Prof. D. Mukhopadhyay. Department of Computer Science and Engineering. Indian Institute of Technology, Kharagpur

Cryptography and Network Security. Prof. D. Mukhopadhyay. Department of Computer Science and Engineering. Indian Institute of Technology, Kharagpur Cryptography and Network Security Prof. D. Mukhopadhyay Department of Computer Science and Engineering Indian Institute of Technology, Kharagpur Module No. # 01 Lecture No. # 12 Block Cipher Standards

More information

OceanStor 9000 InfoProtector Technical White Paper. Issue 01. Date 2014-02-13 HUAWEI TECHNOLOGIES CO., LTD.

OceanStor 9000 InfoProtector Technical White Paper. Issue 01. Date 2014-02-13 HUAWEI TECHNOLOGIES CO., LTD. OceanStor 9000 InfoProtector Technical White Paper Issue 01 Date 2014-02-13 HUAWEI TECHNOLOGIES CO., LTD. Copyright Huawei Technologies Co., Ltd. 2014. All rights reserved. No part of this document may

More information

Lecture 36: Chapter 6

Lecture 36: Chapter 6 Lecture 36: Chapter 6 Today s topic RAID 1 RAID Redundant Array of Inexpensive (Independent) Disks Use multiple smaller disks (c.f. one large disk) Parallelism improves performance Plus extra disk(s) for

More information

Research on massive data storage in virtual roaming system based on RAID5 RAN Feipeng, DAI Huayang, XING Wujie, WANG Xiang, Li Xuesong

Research on massive data storage in virtual roaming system based on RAID5 RAN Feipeng, DAI Huayang, XING Wujie, WANG Xiang, Li Xuesong International Conference on Advances in Mechanical Engineering and Industrial Informatics (AMEII 2015) Research on massive data storage in virtual roaming system based on RAID5 RAN Feipeng, DAI Huayang,

More information

technology brief RAID Levels March 1997 Introduction Characteristics of RAID Levels

technology brief RAID Levels March 1997 Introduction Characteristics of RAID Levels technology brief RAID Levels March 1997 Introduction RAID is an acronym for Redundant Array of Independent Disks (originally Redundant Array of Inexpensive Disks) coined in a 1987 University of California

More information

NetApp RAID-DP : Dual-Parity RAID 6 Protection Without Compromise

NetApp RAID-DP : Dual-Parity RAID 6 Protection Without Compromise White Paper NetApp RAID-DP : Dual-Parity RAID 6 Protection Without Compromise Paul Feresten, NetApp April 2010 WP-7005-0410 EXECUTIVE SUMMARY As disk drive densities continue to increase, and companies

More information

PARALLEL I/O FOR HIGH PERFORMANCE COMPUTING

PARALLEL I/O FOR HIGH PERFORMANCE COMPUTING o. rof. Dr. eter Brezany arallele and Verteilte Datenbanksysteme 1 ARALLEL I/O FOR HIGH ERFORMANCE COMUTING Skriptum zur Vorlesung eter Brezany Institut für Scientific Computing Universität Wien E-Mail:

More information

Database Management Systems

Database Management Systems 4411 Database Management Systems Acknowledgements and copyrights: these slides are a result of combination of notes and slides with contributions from: Michael Kiffer, Arthur Bernstein, Philip Lewis, Anestis

More information

Disks and RAID. Profs. Bracy and Van Renesse. based on slides by Prof. Sirer

Disks and RAID. Profs. Bracy and Van Renesse. based on slides by Prof. Sirer Disks and RAID Profs. Bracy and Van Renesse based on slides by Prof. Sirer 50 Years Old! 13th September 1956 The IBM RAMAC 350 Stored less than 5 MByte Reading from a Disk Must specify: cylinder # (distance

More information

Standard RAID levels - Wikipedia, the free encycl...

Standard RAID levels - Wikipedia, the free encycl... Standard RAID levels From Wikipedia, the free encyclopedia Wikipedia is sustained by people like you. Please donate today. The st andard RAID levels are a basic set of RAID configurations and employ striping,

More information

Case for storage. Outline. Magnetic disks. CS2410: Computer Architecture. Storage systems. Sangyeun Cho

Case for storage. Outline. Magnetic disks. CS2410: Computer Architecture. Storage systems. Sangyeun Cho Case for storage CS24: Computer Architecture Storage systems Sangyeun Cho Computer Science Department Shift in focus from computation to communication & storage of information Eg, Cray Research/Thinking

More information

RAID: Redundant Arrays of Inexpensive Disks this discussion is based on the paper: on Management of Data (Chicago, IL), pp.109--116, 1988.

RAID: Redundant Arrays of Inexpensive Disks this discussion is based on the paper: on Management of Data (Chicago, IL), pp.109--116, 1988. : Redundant Arrays of Inexpensive Disks this discussion is based on the paper:» A Case for Redundant Arrays of Inexpensive Disks (),» David A Patterson, Garth Gibson, and Randy H Katz,» In Proceedings

More information

Solving Data Loss in Massive Storage Systems Jason Resch Cleversafe

Solving Data Loss in Massive Storage Systems Jason Resch Cleversafe Solving Data Loss in Massive Storage Systems Jason Resch Cleversafe 2010 Storage Developer Conference. Insert Your Company Name. All Rights Reserved. 1 In the beginning There was replication Long before

More information

Note: Correction to the 1997 Tutorial on Reed-Solomon Coding

Note: Correction to the 1997 Tutorial on Reed-Solomon Coding Note: Correction to the 1997 utorial on Reed-Solomon Coding James S Plank Ying Ding University of ennessee Knoxville, N 3799 [plank,ying]@csutkedu echnical Report U-CS-03-504 Department of Computer Science

More information

= 2 + 1 2 2 = 3 4, Now assume that P (k) is true for some fixed k 2. This means that

= 2 + 1 2 2 = 3 4, Now assume that P (k) is true for some fixed k 2. This means that Instructions. Answer each of the questions on your own paper, and be sure to show your work so that partial credit can be adequately assessed. Credit will not be given for answers (even correct ones) without

More information

A A Hybrid Approach of Failed Disk Recovery Using RAID-6 Codes: Algorithms and Performance Evaluation

A A Hybrid Approach of Failed Disk Recovery Using RAID-6 Codes: Algorithms and Performance Evaluation A A Hybrid Approach of Failed Disk Recovery Using RAID-6 Codes: Algorithms and Performance Evaluation LIPING XIANG and YINLONG XU, University of Science and Technology of China JOHN C.S. LUI, The Chinese

More information

A Performance Evaluation and Examination of Open-Source Erasure Coding Libraries For Storage

A Performance Evaluation and Examination of Open-Source Erasure Coding Libraries For Storage A Performance Evaluation and Examination of Open-Source Erasure Coding Libraries For Storage James S. Plank University of Tennessee plank@cs.utk.edu Lihao Xu Wayne State University Jianqiang Luo Wayne

More information

Improving Lustre OST Performance with ClusterStor GridRAID. John Fragalla Principal Architect High Performance Computing

Improving Lustre OST Performance with ClusterStor GridRAID. John Fragalla Principal Architect High Performance Computing Improving Lustre OST Performance with ClusterStor GridRAID John Fragalla Principal Architect High Performance Computing Legacy RAID 6 No Longer Sufficient 2013 RAID 6 data protection challenges Long rebuild

More information

Design and Implementation of a Storage Repository Using Commonality Factoring. IEEE/NASA MSST2003 April 7-10, 2003 Eric W. Olsen

Design and Implementation of a Storage Repository Using Commonality Factoring. IEEE/NASA MSST2003 April 7-10, 2003 Eric W. Olsen Design and Implementation of a Storage Repository Using Commonality Factoring IEEE/NASA MSST2003 April 7-10, 2003 Eric W. Olsen Axion Overview Potentially infinite historic versioning for rollback and

More information

NCCloud: A Network-Coding-Based Storage System in a Cloud-of-Clouds

NCCloud: A Network-Coding-Based Storage System in a Cloud-of-Clouds 1 NCCloud: Network-Coding-ased Storage System in a Cloud-of-Clouds Henry C. H. Chen, Yuchong Hu, Patrick P. C. Lee, and Yang Tang bstract To provide fault tolerance for cloud storage, recent studies propose

More information

Filing Systems. Filing Systems

Filing Systems. Filing Systems Filing Systems At the outset we identified long-term storage as desirable characteristic of an OS. EG: On-line storage for an MIS. Convenience of not having to re-write programs. Sharing of data in an

More information

Erasure Coding in Windows Azure Storage

Erasure Coding in Windows Azure Storage Erasure Coding in Windows Azure Storage Cheng Huang Microsoft Corporation Joint work with Huseyin Simitci, Yikang Xu, Aaron Ogus, Brad Calder, Parikshit Gopalan, Jin Li, and Sergey Yekhanin Outline Introduction

More information

XtremIO DATA PROTECTION (XDP)

XtremIO DATA PROTECTION (XDP) White Paper XtremIO DATA PROTECTION (XDP) Flash-Specific Data Protection, Provided by XtremIO (Ver..0) Abstract This white paper introduces the and discusses its benefits and advantages over RAID, with

More information

A HIGHLY RELIABLE GPU-BASED RAID SYSTEM MATTHEW L. CURRY

A HIGHLY RELIABLE GPU-BASED RAID SYSTEM MATTHEW L. CURRY A HIGHLY RELIABLE GPU-BASED RAID SYSTEM by MATTHEW L. CURRY ANTHONY SKJELLUM, COMMITTEE CHAIR PURUSHOTHAM V. BANGALORE ROBERT M. HYATT ARKADY KANEVSKY JOHN D. OWENS BORIS PROTOPOPOV A DISSERTATION Submitted

More information

CSE-E5430 Scalable Cloud Computing P Lecture 5

CSE-E5430 Scalable Cloud Computing P Lecture 5 CSE-E5430 Scalable Cloud Computing P Lecture 5 Keijo Heljanko Department of Computer Science School of Science Aalto University keijo.heljanko@aalto.fi 12.10-2015 1/34 Fault Tolerance Strategies for Storage

More information

Three-Dimensional Redundancy Codes for Archival Storage

Three-Dimensional Redundancy Codes for Archival Storage Three-Dimensional Redundancy Codes for Archival Storage Jehan-François Pâris Darrell D. E. Long Witold Litwin Department of Computer Science University of Houston Houston, T, USA jfparis@uh.edu Department

More information

File System & Device Drive. Overview of Mass Storage Structure. Moving head Disk Mechanism. HDD Pictures 11/13/2014. CS341: Operating System

File System & Device Drive. Overview of Mass Storage Structure. Moving head Disk Mechanism. HDD Pictures 11/13/2014. CS341: Operating System CS341: Operating System Lect 36: 1 st Nov 2014 Dr. A. Sahu Dept of Comp. Sc. & Engg. Indian Institute of Technology Guwahati File System & Device Drive Mass Storage Disk Structure Disk Arm Scheduling RAID

More information

StorTrends RAID Considerations

StorTrends RAID Considerations StorTrends RAID Considerations MAN-RAID 04/29/2011 Copyright 1985-2011 American Megatrends, Inc. All rights reserved. American Megatrends, Inc. 5555 Oakbrook Parkway, Building 200 Norcross, GA 30093 Revision

More information

Operating Systems. RAID Redundant Array of Independent Disks. Submitted by Ankur Niyogi 2003EE20367

Operating Systems. RAID Redundant Array of Independent Disks. Submitted by Ankur Niyogi 2003EE20367 Operating Systems RAID Redundant Array of Independent Disks Submitted by Ankur Niyogi 2003EE20367 YOUR DATA IS LOST@#!! Do we have backups of all our data???? - The stuff we cannot afford to lose?? How

More information

ECE 842 Report Implementation of Elliptic Curve Cryptography

ECE 842 Report Implementation of Elliptic Curve Cryptography ECE 842 Report Implementation of Elliptic Curve Cryptography Wei-Yang Lin December 15, 2004 Abstract The aim of this report is to illustrate the issues in implementing a practical elliptic curve cryptographic

More information

VERY IMPORTANT NOTE! - RAID

VERY IMPORTANT NOTE! - RAID Disk drives are an integral part of any computing system. Disk drives are usually where the operating system and all of an enterprise or individual s data are stored. They are also one of the weakest links

More information

Securing Cloud Data Storage

Securing Cloud Data Storage IOSR Journal of Computer Engineering (IOSRJCE) ISSN: 2278-0661 Volume 1, Issue 6 (July-Aug. 2012), PP 43-49 Securing Cloud Data Storage S. P. Jaikar 1, M. V. Nimbalkar 2 1,2 (Department of Information

More information

Mathematics of Cryptography

Mathematics of Cryptography CHAPTER 2 Mathematics of Cryptography Part I: Modular Arithmetic, Congruence, and Matrices Objectives This chapter is intended to prepare the reader for the next few chapters in cryptography. The chapter

More information

Erasure Codes Made So Simple, You ll Really Like Them

Erasure Codes Made So Simple, You ll Really Like Them Erasure Codes Made So Simple, You ll Really Like Them W. David Schwaderer August 7, 214 schwaderer_1@comcast.net Santa Clara, CA 1 Agenda Errors Versus Erasures HDD Bit Error Rate Implications RAID 4,

More information

Sonexion GridRAID Characteristics

Sonexion GridRAID Characteristics Sonexion GridRAID Characteristics Mark Swan Performance Team Cray Inc. Saint Paul, Minnesota, USA mswan@cray.com Abstract This paper will present performance characteristics of the Sonexion declustered

More information

RAID Technology Overview

RAID Technology Overview RAID Technology Overview HP Smart Array RAID Controllers HP Part Number: J6369-90050 Published: September 2007 Edition: 1 Copyright 2007 Hewlett-Packard Development Company L.P. Legal Notices Copyright

More information

RAID HARDWARE. On board SATA RAID controller. RAID drive caddy (hot swappable) SATA RAID controller card. Anne Watson 1

RAID HARDWARE. On board SATA RAID controller. RAID drive caddy (hot swappable) SATA RAID controller card. Anne Watson 1 RAID HARDWARE On board SATA RAID controller SATA RAID controller card RAID drive caddy (hot swappable) Anne Watson 1 RAID The word redundant means an unnecessary repetition. The word array means a lineup.

More information

Cloud Storage over Multiple Data Centers

Cloud Storage over Multiple Data Centers Cloud Storage over Multiple Data Centers Shuai MU, Maomeng SU, Pin GAO, Yongwei WU, Keqin LI, Albert ZOMAYA 0 Abstract The increasing popularity of cloud storage services has led many companies to migrate

More information

Outline. Database Management and Tuning. Overview. Hardware Tuning. Johann Gamper. Unit 12

Outline. Database Management and Tuning. Overview. Hardware Tuning. Johann Gamper. Unit 12 Outline Database Management and Tuning Hardware Tuning Johann Gamper 1 Free University of Bozen-Bolzano Faculty of Computer Science IDSE Unit 12 2 3 Conclusion Acknowledgements: The slides are provided

More information

The Pros and Cons of Erasure Coding & Replication vs. RAID in Next-Gen Storage Platforms. Abhijith Shenoy Engineer, Hedvig Inc.

The Pros and Cons of Erasure Coding & Replication vs. RAID in Next-Gen Storage Platforms. Abhijith Shenoy Engineer, Hedvig Inc. The Pros and Cons of Erasure Coding & Replication vs. RAID in Next-Gen Storage Platforms Abhijith Shenoy Engineer, Hedvig Inc. @hedviginc The need for new architectures Business innovation Time-to-market

More information

arxiv:1302.3344v2 [cs.dc] 6 Jun 2013

arxiv:1302.3344v2 [cs.dc] 6 Jun 2013 CORE: Augmenting Regenerating-Coding-Based Recovery for Single and Concurrent Failures in Distributed Storage Systems arxiv:1302.3344v2 [cs.dc] 6 Jun 2013 Runhui Li, Jian Lin, Patrick Pak-Ching Lee Department

More information

CS161: Operating Systems

CS161: Operating Systems CS161: Operating Systems Matt Welsh mdw@eecs.harvard.edu Lecture 18: RAID April 19, 2007 2007 Matt Welsh Harvard University 1 RAID Redundant Arrays of Inexpensive Disks Invented in 1986-1987 by David Patterson

More information

An Area-Efficient Architecture of Reed-Solomon Codec for Advanced RAID Systems Min-An Song, I-Feng Lan, and Sy-Yen Kuo

An Area-Efficient Architecture of Reed-Solomon Codec for Advanced RAID Systems Min-An Song, I-Feng Lan, and Sy-Yen Kuo An Area-Efficient Architecture of Reed-olomon Codec for Advanced RAID ystems Min-An ong, I-Feng Lan, and y-yen Kuo Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan E-mail:

More information

Guide to SATA Hard Disks Installation and RAID Configuration

Guide to SATA Hard Disks Installation and RAID Configuration Guide to SATA Hard Disks Installation and RAID Configuration 1. Guide to SATA Hard Disks Installation... 2 1.1 Serial ATA (SATA) Hard Disks Installation... 2 2. Guide to RAID Configurations... 3 2.1 Introduction

More information