Florida State University Libraries Electronic Theses, Treatises and Dissertations The Graduate School 2005 Iscsi-Based Storage Area Networks for Disaster Recovery Operations Matthew R. Murphy Follow this and additional works at the FSU Digital Library. For more information, please contact [email protected] THE FLORIDA STATE UNIVERSITY COLLEGE OF ENGINEERING iSCSI-based Storage Area Networks for Disaster Recovery Operations By MATTHEW R. MURPHY A Thesis submitted to the Department of Electrical and Computer Engineering in partial fulfillment of the requirements for the degree of Master of Science Degree Awarded: Spring Semester, 2005 The members of the Committee approve the thesis of Matthew R. Murphy defended on April 5, 2005. ______________________________ Bruce A. Harvey Professor Directing Thesis ______________________________ Lois Hawkes Committee Member ___________________________________ Simon Foo Committee Member ___________________________________ Michael Frank Committee Member Approved: _____________________________________________ Leonard Tung, Chair, Department of Electrical & Computer Engineering The Office of Graduate Studies has verified and approved the above named committee members. ii TABLE OF CONTENTS List of Figures..................................................................................................................... v List of Tables ..................................................................................................................... vi ABSTRACT...................................................................................................................... vii INTRODUCTION .............................................................................................................. 1 1. DISASTER RECOVERY............................................................................................... 3 1.1 Recovery Time and Recovery Point Objectives ....................................................... 3 1.2 Increasing Assurance using Remote Backup............................................................ 5 1.3 The Emergence of Storage Area Networks .............................................................. 6 1.4 Fibre Channel Protocol ............................................................................................. 7 1.4.1 The Trouble with Fibre Channel............................................................................ 8 1.5 Origins of iSCSI........................................................................................................ 9 1.5.1 Solutions Provided by iSCSI ............................................................................... 10 1.6 iSCSI vs. NFS ......................................................................................................... 13 2. DISASTER RECOVERY USING iSCSI ..................................................................... 16 2 Fundamentals of iSCSI .............................................................................................. 16 2.1 The Protocol Data Unit ........................................................................................... 17 2.1.1 PDU Structure...................................................................................................... 17 2.2 Layer Interactions ................................................................................................... 18 2.3 iSCSI Login ............................................................................................................ 20 2.3.1 Login Request PDU ............................................................................................. 20 2.3.2 Login Response PDU........................................................................................... 22 2.4 Login Text Parameters............................................................................................ 23 2.4.1 Text Request and Response PDUs....................................................................... 24 2.5 SCSI Read and Write Operations ........................................................................... 25 2.6 iSCSI Discovery Sessions....................................................................................... 27 2.7 Disaster Recovery using iSCSI............................................................................... 28 2.7.1 Small Business Continuity of Operations............................................................ 29 2.7.2 Enterprise Continuity of Operations .................................................................... 30 2.7.3 Remote Backup using iSCSI for Large Organizations ........................................ 32 2.8 Software and Hardware iSCSI Implementations .................................................... 32 2.8.1 Software-based iSCSI .......................................................................................... 33 2.8.2 TCP/IP Offload Engines ...................................................................................... 34 2.8.3 Hardware-based iSCSI......................................................................................... 35 2.8.4 Comparison of Hardware and Software-based iSCSI.......................................... 35 2.9 Cancer Therapy and Research Center Case Study.................................................. 36 2.9.1 Background and Requirements............................................................................ 37 2.9.2 An IP SAN Solution............................................................................................. 38 2.9.3 Results and Performance...................................................................................... 39 2.10 iSCSI RAID Configurations ................................................................................. 40 2.10.1 Distributed iSCSI RAID Configurations ........................................................... 42 2.11 MC/S and Link Aggregation................................................................................. 43 iii 2.11.1 Ensuring In-order PDU Delivery over MC/S .................................................... 45 2.11.2 Benefits of Using MC/S..................................................................................... 46 2.11.3 MC/S Implementation Results........................................................................... 47 2.12 Limitations of iSCSI ............................................................................................. 48 2.12.1 Fault Tolerance .................................................................................................. 48 2.12.2 Load Balancing and Manageability ................................................................... 51 3. PERFORMANCE TESTING OF iSCSI....................................................................... 53 3 Software-based iSCSI Experiments........................................................................... 53 3.1 iSCSI Testbed ......................................................................................................... 53 3.2 Block Size and Throughput .................................................................................... 54 3.2.1 Fast Ethernet Results............................................................................................ 54 3.2.2 Gigabit Ethernet Results ...................................................................................... 55 3.3 iSCSI CPU Utilization ............................................................................................ 58 3.4 CPU Loading Effects on iSCSI Throughput........................................................... 60 3.5 iSCSI at 10 Gbps..................................................................................................... 61 4. CONCLUSION............................................................................................................. 64 APPENDIX....................................................................................................................... 67 REFERENCES ................................................................................................................. 70 BIOGRAPHICAL SKETCH ............................................................................................ 73 iv LIST OF FIGURES Figure 1 – Minimum distance recommendations (in miles) ............................................... 5 Figure 2 – Generic Storage Area Network ......................................................................... 7 Figure 3 – iSCSI Encapsulation........................................................................................ 11 Figure 4 – iSCSI as a remote backup mechanism............................................................. 12 Figure 5 – SCSI device interaction ................................................................................... 16 Figure 6 – PDU and BHS Structure.................................................................................. 18 Figure 7 – iSCSI Layer Interactions ................................................................................. 19 Figure 8 – Login Request PDU......................................................................................... 20 Figure 9 – Login Response PDU ...................................................................................... 22 Figure 10 – Text Request PDU......................................................................................... 24 Figure 11 – Text Response PDU .....................................................................................