Synopses & Reviews
iSCSI: The Universal Storage Connection
is an informative overview and in-depth guide to the emerging iSCSI standard, the technology that enables data storage, access, and management over networks, intranets, and the Internet. The iSCSI protocol reduces the total cost of ownership of shared storage solutions and enables an organization to tie together disparate systems and data, including both server class systems and laptop and desktop systems. Numerous leading technology companies, including IBM®, Cisco Systems®, and Intel®, are currently supporting iSCSI initiatives.
Written for network and data storage professionals, this comprehensive book introduces iSCSI and explores its growing role within the data storage industry. It describes each element of the technology in detail—from session establishment through error handling—and examines the relationship between iSCSI and the SCSI protocol from which it evolved.
Specific topics discussed include:
- iSCSI's use in small office, midrange, and high-end settings
- TCP/IP fundamentals, and how they apply to iSCSI
- The importance of data integrity
- New hardware that addresses bandwidth and latency issues
- iSCSI naming conventions
- The establishment of a communication path between the host system and storage controller
- Commands and data sequencing
- Control of the flow of commands
- Task management
- Error handling
- Companion technologies, including discovery and security processes
- Backup and disaster preparation
- iSCSI performance issues
In addition, the book includes an explanation of the technologies that hardware vendors are implementing to permit direct memory placement of iSCSI messages without additional main processor involvement.
A helpful icon appears throughout the book, mapping out appropriate reading tracks based on your technical level.
Comprehensive, clearly written, and organized for easy access, this iSCSI handbook serves as both an excellent starting point for those involved in data storage solutions and a guide to understanding the technically detailed Internet Engineering Task Force (IETF) iSCSI Standards document.
The new iSCSI protocol carries SCSI commands over IP networks to facilitate data transfers over intranets and to manage storage over long distances. This book offers System and Storage engineers a quick and easy way to become familiar with the iSCSI protocols with needed insight to its applicability.
Includes bibliographical references (p. 323-327) and index.
About the Author
John L. Hufferd
has been a key technical leader and manager within IBM for more than thirty-five years and currently directs projects dealing with networks, storage, and SANs. He is the technical coordinator for the iSCSI track of the IPS workgroup in the IETF standards association.
Table of Contents
(NOTE: Each chapter, except Chapter 1, begins with To the Reader and all chapters conclude with a Summary.
Credits and Disclaimer.
1. The Background of SCSI.
SCSI BUS Interconnect.
Fibre Channel Interconnect.
File Servers and NAS.
2. The Value and Position of iSCSI.
The Home Office.
The Home Office and Serial ATA Drives.
The Small Office.
The High End.
The At-Distance Site.
The Central Site.
FC and iSCSI.
3. The History of iSCSI.
SCSI Over TCP/IP.
Cisco and IBM's Joint Effort.
iSCSI and IETF.
The End of the Story.
4. An Overview of iSCSI.
iSCSI-Related Protocol Layers.
Protocol Data Unit (PDU) Structure.
PDU Structure Summary.
iSCSI and TOE Integration on a Chip or HBA.
TOE Integration Summary.
Checksums and CRC (Digests).
Checksum and CRC Digest Summary.
Naming and Addressing.
Details of Naming and Addressing.
Naming and Addressing Summary.
5. Session Establishment.
Introduction to the Login Process.
Login and Session Establishment.
The Login Request PDU.
The Login Response PDU.
Keywords and the Login Process.
6. Text Commands and Keyword Processing.
Text Requests and Responses.
Text Keywords and Responses.
Rules for Key=Value Pairs.
Rules for Keyword Value Negotiation.
Rules for Negotiation Flow.
Rules for Negotiation Failure.
7. Session Management.
Initiator Session ID.
Data Travel Direction.
Resending Data or Status.
8. Command and Data Ordering and Flow.
Initiator Task Tag.
Design Example: Direct Host Memory Placement.
Target Transfer Tag.
Data Placement (A Form of RDMA).
9. Structure of iSCSI and Relationship to SCSI.
iSCSI Structure and SCSI Relationship.
10. Task Management.
Tagged and Untagged Texts.
11. Error Handling.
Error Recovery Levels.
Error Recovery Level 0.
Error Recovery Level 1.
Header Digest Recovery at the Initiator Side.
Header Digest Recovery at the Target Side.
Data Digest Recovery.
Error Recovery Level 2.
12. Companion Processes.
Discovery Using Administrative Specifications.
Discovery Using SendTargets.
Discovery Using the Service Location Protocol.
Discovery Using iSNS.
To the Reader.
Access Control Lists.
MIB AND SNMP.
13. Synchronization and Steering.
Main Memory Replacement.
Errors and Congestion.
Missing TCP Segments and Marking.
FIM Synchronization Scheme.
TCP Upper-Level-Protocol Framing (TUF).
The TUF Scheme.
The TUF Header.
Advantages and Disadvantages.
14. iSCSI Summary and Conclusions.
iSCSI Development History.
iSCSI Network Management.
Ease of Administration.
Backup and Disaster Preparation.
Summary of Conclusions.
Appendix A: iSCSI Function PDUs.
Serial Number Arithmetic.
Asynchronous Message PDU.
Login Request PDU.
ISID, TSIH, and CID Values.
Login Response PDU.
Logout Request PDU.
Notes on the Logout Request PDU.
Implicit Termination of Tasks.
Logout Response PDU.
Ready to Transfer (R2T) PDU.
Notes on the R2T PDU.
Notes on the Reject PDU.
SCSI (Command) Request PDU.
SCSI (Command) Response PDU.
SCSI Data-In PDU.
SCSI Data-Out PDU.
SNACK Request PDU.
Notes on the SNACK Request PDU.
Task Management Function Request PDU.
Notes on the Task Management Function Request PDU.
Task Management Function Response PDU.
Notes on the Task Management Function Response PDU.
Text Request PDU.
Text Response PDU.
Appendix B: Keys and Values.
Appendix C: SCSI Architecture Model.
Consequences of the Model.
I-T Nexus State.
SCSI Mode Pages.
Appendix D: Numbers, Characters, and Bit Encodings.
Appendix E: Definitions.
Appendix F: Acronyms.
Appendix G. References and Web Pointers.
Basic References for iSCSI.
References for SCSI-Related Items.
References for iSCSI Security and IPsec/IKE.
References That Indirectly Affect iSCSI.