Florida International University FIU Digital Commons FIU Electronic Theses and Dissertations University Graduate School 3-28-1994 Performance analysis of disk mirroring techniques Taysir Abdalla Florida International University DOI: 10.25148/etd.FI13101501 Follow this and additional works at: https://digitalcommons.fiu.edu/etd Part of the Computer Sciences Commons Recommended Citation Abdalla, Taysir, "Performance analysis of disk mirroring techniques" (1994). FIU Electronic Theses and Dissertations. 1061. https://digitalcommons.fiu.edu/etd/1061 This work is brought to you for free and open access by the University Graduate School at FIU Digital Commons. It has been accepted for inclusion in FIU Electronic Theses and Dissertations by an authorized administrator of FIU Digital Commons. For more information, please contact [email protected]. FLORIDA INTERNATIONAL UNIVERSITY Miami, Florida PERFORMANCE ANALYSIS OF DISK MIRRORING TECHNIQUES A thesis submitted in partial satisfaction of the requirements for the degree of MASTER OF SCIENCE IN COMPUTER SCIENCE By Taysir Abdalla 1994 To: Arthur W. Herriott College of Arts and Sciences This thesis, written by Taysir Abdalla, and entitled Performance Analysis of Disk Mirroring Techniques, having been approved in respect to style and intellectual content, is referred to you for judgment We have read this thesis and recommend that it be approved. Dawn Holmes Ra'mund Ege Nagarajan Prabhakaran Cyril Org, Major Professor Date of Defense: March 28, 1994 The thesis of Taysir Abdalla is approved. Dean Arthur W. Herriott Colge of Arts and Sciences Dr. Richard L. Campb >l Dean of Graduate Studies Florida International University, 1994 ii ©COPYRIGHT 1994 by Taysir Abdalla All rights reserved iii ACKNOWLEDGMENTS I wish to thank my advisor, Dr. Orji, for his continuos support and encouragement. I also want to thank the members of my committee - Raimund Ege, Nagarajan Prabhakaran and Dawn Holmes. iv ABSTRACT OF THE THESIS Performance Analysis of Disk Mirroring Techniques By Taysir Abdalla Florida International University, 1994 Miami, Florida Professor Cyril Orji, Major Professor Unequaled improvements in processor and I/O speeds make many applications such as databases and operating systems to be increasingly I/O bound. Many schemes such as disk caching and disk mirroring have been proposed to address the problem. In this thesis we focus only on disk mirroring. In disk mirroring, a logical disk image is maintained on two physical disks allowing a single disk failure to be transparent to application programs. Although disk mirroring improves data availability and reliability, it has two major drawbacks. First, writes are expensive because both disks must be updated. Second, load balancing during failure mode operation is poor because all requests are serviced by the surviving disk. Distorted mirrors was proposed to address the write problem and interleaved declustering to address the load balancing problem. In this thesis we perform a comparative study of these two schemes under various operating modes. In addition we also study traditional mirroring to provide a common basis for comparison. TABLE OF CONTENTS CHAPTER PAGE 1. INTRODUCTION 1.1 The Pending I/O Crisis........................................................ 1 1.2 Proposed Solutions............................................................... 2 1.3 Mirroring Techniques .......................................................... 4 1.3.1 Traditional Mirroring ........................................... 4 1.3.2 Distorted Mirroring ............................................... 5 1.3.3 Interleaved Declustering ...................................... 7 1.4 Statement of the Problem.................................................... 8 1.5 R elated W ork ....................................................................... 9 1.6 Thesis O bjective.................................................................... 11 2. THE SIMULATOR 2.1 Simulation Model................................................................ 13 2.2 Rebuild Algorithms.............................................................. 16 2.2.1 Traditional Mirroring ............................................ 16 2.2.1 Distorted Mirroring ............................................... 17 2.2.1 Interleaved Declustering ....................................... 19 3. SIMULATION RESULTS 3.1 Performance Metrics ............................................................ 21 3.2 N orm al M ode........................................................................ 21 3.3 Degraded Mode.................................................................... 24 3.4 R ebuild M ode ....................................................................... 27 3.5 Other Read/Write Ratios..................................................... 38 4. CONCLUSION 4.1 C ontributions........................................................................ 43 4.2 Future Directions.................................................................. 44 LIST OF REFERENCES ......................................................................... .46 Vi LIST OF TABLES TABLE PAGE I Iterleaved Declustering: A cluster of 8 Disks ......................... 14 II Disk and W orkload Parameters................................................ 15 III Response and Rebuild Time Data at 200 I/Os Per Second (N o Redirection of Read)........................................................... 37 IV Response and Rebuild Time Data at 200 I/Os Per Second (With Redirection of Read)......................................................... 37 vii LIST OF FIGURES FIGURE PAGE 1 Disk A rrays (RA ID )........................................................................................ 3 2 Traditional Mirroring (Mirror set = 2) ........................................................ 5 3 D istorted M irroring ...................................................................................... 6 4 Interleaved Declustering (Cluster size = 4)................................................. 8 5 90th Percentile Read Response Time vs I/O Rate (50% read) (Normal Mode) .............................................................................................. 22 6 90th Percentile Read Response Time vs I/O Rate (75% read) (N orm al M ode).............................................................................................. 22 7 Disk Utilization vs I/O Rate (75% read: Normal Mode)............................. 23 8 90th Percentile Read Response Time vs I/O Rate (50% read) (Degraded Mode - All requests).................................................................... 24 9 90th Percentile Read Response Time vs I/O Rate (75% read) (Degraded M ode - All requests).................................................................. 25 10 90th Percentile Read Response Time vs I/O Rate (50% read) (Degraded Mode - Only requests to failed disk).......................................... 26 11 90th Percentile Read Response Time vs I/O Rate (75% read) (Degraded Mode - Only requests to failed disk).......................................... 26 12 90th Percentile Read Response Time vs I/O Rate (50% read) (Rebuild Mode - All requests - Block rebuild unit).................................... 27 13 90th Percentile Read Response Time vs I/O Rate (75% read) (Rebuild Mode - All requests - Block rebuild unit).................................... 28 14 90th Percentile Read Response Time vs I/O Rate (50% read) (Rebuild Mode - Only requests to failed disk - Block rebuild unit)............ 28 viii LIST OF FIGURES FIGURE PAGE 1 D isk A rrays (RA ID )...................................................................................... 3 2 Traditional Mirroring (Mirror set = 2) .......................................................... 5 3 D istorted M irroring ...................................................................................... 6 4 Interleaved Declustering (Cluster size = 4)................................................. 8 5 90th Percentile Read Response Time vs I/O Rate (50% read) (Normal Mode) ............................................................................................. 22 6 90th Percentile Read Response Time vs I/O Rate (75% read) (Normal Mode) ............................................................................................. 22 7 Disk Utilization vs I/O Rate (75% read: Normal Mode)............................. 23 8 90th Percentile Read Response Time vs I/O Rate (50% read) (Degraded Mode - All requests).................................................................... 24 9 90th Percentile Read Response Time vs I/O Rate (75% read) (Degraded Mode - All requests).................................................................... 25 10 90th Percentile Read Response Time vs I/O Rate (50% read) (Degraded Mode - Only requests to failed disk).......................................... 26 11 90th Percentile Read Response Time vs I/O Rate (75% read) (Degraded Mode - Only requests to failed disk).......................................... 26 12 90th Percentile Read Response Time vs I/O Rate (50% read) (Rebuild Mode - All requests - Block rebuild unit).................................... 27 13 90th Percentile Read Response Time vs I/O Rate (75% read) (Rebuild Mode - All requests - Block rebuild unit).................................... 28 14 90th Percentile Read Response Time vs I/O Rate (50% read) (Rebuild Mode - Only requests to failed disk - Block rebuild unit)............ 28 viii LIST OF FIGURES (continued) FIGURE PAGE