Storage Networks Explained: Basics and Application of Fibre Channel SAN, NAS, iSCSI, InfiniBand and FCoE, 2nd Edition
The amount of data of an average company doubles every year. Thus, companies who own 1TB of data today will own 32TB in five years. Storage networks help to tame such data quantities and to manage this data growth efficiently. Since stored data and information are the biggest asset of any company, anyone who is involved in the planning or the operation of IT systems requires a basic knowledge of the principle and the use of storage networks.
Storage Networks Explained covers the fundaments, techniques and functions of storage networks such as disk subsystems, Fibre Channel SAN, Internet SCSI (iSCSI), Fibre Channel over Ethernet (FCoE), Network Attached Storage (NAS), file systems, and storage virtualization. Furthermore the authors describe the use of these techniques and how they are designed to achieve high-availability, flexibility, and scalability of data and applications. Additional attention is given to network backup and the management of storage networks. Written by leading experts in the field, this book on storage area networks is updated and fully revised.
Presents the basic concepts of storage networks, such as I/O techniques, disk subsystems, virtualization, NAS and SAN file systems
Covers the design of storage networks which provide flexible, highly-available, and scaleable IT systems
Explains the use of storage networks for data sharing, data protection, and digital archiving
Discusses management of storage networks using SNMP, SMI-S, and IEEE 1244
This book provides system administrators and system architects, as well as students and decision makers, with the tools needed for optimal selection and cost-effective use of storage networks.
The Linux Journal awarded the first edition with the “Editor’s Choice Award 2005” in the category “System Administration Book.”
Foreword to the Second Edition by Hermann Strass.
Preface by the Authors.
List of Figures and Tables.
1.1 Server-Centric IT Architecture and its Limitations.
1.2 Storage-Centric IT Architecture and its Advantages.
1.3 Case Study: Replacing a Server with Storage Networks.
1.4 The Structure of the Book.
PART I Technologies for Storage Networks.
2 Intelligent Disk Subsystems.
2.1 Architecture of Intelligent Disk Subsystems.
2.2 Hard Disks and Internal I/O Channels.
2.3 JBOD: Just a Bunch of Disks.
2.4 Storage Virtualisation Using RAID.
2.5 Different RAID Levels in Detail.
2.5.1 RAID 0: block-by-block striping.
2.5.2 RAID 1: block-by-block mirroring.
2.5.3 RAID 0+1/RAID 10: striping and mirroring combined.
2.5.4 RAID 4 and RAID 5: parity instead of mirroring.
2.5.5 RAID 6: double parity.
2.5.6 RAID 2 and RAID 3.
2.5.7 A comparison of the RAID levels.
2.6 Caching: Acceleration of Hard Disk Access.
2.6.1 Cache on the hard disk.
2.6.2 Write cache in the disk subsystem controller.
2.6.3 Read cache in the disk subsystem controller.
2.7 Intelligent Disk Subsystems.
2.7.1 Instant copies.
2.7.2 Remote mirroring.
2.7.3 Consistency groups.
2.7.4 LUN masking.
2.8 Availability of Disk Subsystems.
3 I/O Techniques.
3.1 The Physical I/O Path from the CPU to the Storage System.
3.2.1 SCSI basics.
3.2.2 SCSI and storage networks.
3.3 The Fibre Channel Protocol Stack.
3.3.1 Links, ports and topologies.
3.3.2 FC-0: cables, plugs and signal encoding.
3.3.3 FC-1: 8b/10b encoding, ordered sets and link control protocol.
3.3.4 FC-2: data transfer.
3.3.5 FC-3: common services.
3.3.6 Link services: login and addressing.
3.3.7 Fabric services: name server and co.
3.3.8 FC-4 and ULPs: application protocols.
3.4 Fibre Channel SAN.
3.4.1 Point-to-point topology.
3.4.2 Fabric topology.
3.4.3 Arbitrated loop topology.
3.4.4 Hardware components for Fibre Channel SAN.
3.4.6 Interoperability of Fibre Channel SAN.
3.5 IP Storage.
3.5.1 IP storage standards: iSCSI, iFCP, mFCP, FCIP and iSNS.
3.5.2 TCP/IP and Ethernet as an I/O technology.
3.5.3 Migration from Fibre Channel to IP storage.
3.6 Infiniband-based Storage Networks.
3.6.2 Virtual Interface Architecture (VIA).
3.6.3 SCSI via InfiniBand and RDMA.
3.7 Fibre Channel over Ethernet (FCoE).
3.7.1 I/O Consolidation based on Ethernet.
3.7.2 FCoE Details.
3.7.3 Case studies.
3.7.4 Data Center Bridging (DCB).
4 File Systems and Network Attached Storage (NAS).
4.1 Local File Systems.
4.1.1 File systems and databases.
4.1.4 Volume manager.
4.2 Network File Systems and File Servers.
4.2.1 Basic principle.
4.2.2 Network Attached Storage (NAS).
4.2.3 Performance bottlenecks in file servers.
4.2.4 Acceleration of network file systems.
4.2.5 Case study: The Direct Access File System (DAFS).
4.3 Shared Disk File Systems.
4.3.1 Case study: The General Parallel File System (GPFS).
4.4 Comparison: Fibre Channel SAN, FCoE SAN, iSCSI SAN and NAS.
5 Storage Virtualisation.
5.1 Once Again: Virtualisation in the I/O Path.
5.2 Limitations and Requirements.
5.2.1 Architecture-related limitations of non-virtualised storage networks.
5.2.2 Implementation-related limitations of storage networks.
5.2.3 Requirements of the data.
5.2.4 Proposed solution: storage virtualisation.
5.3 Definition of Storage Virtualisation.
5.4 Implementation Considerations.
5.4.1 Realisation of the virtualisation entity.
5.4.2 Replacement of storage devices.
5.4.3 Efficient use of resources by dynamic storage allocation.
5.4.4 Efficient use of resources by data migration.
5.4.5 Performance increase.
5.4.6 Availability due to the introduction of redundancy.
5.4.7 Backup and archiving.
5.4.8 Data sharing.
5.4.9 Privacy protection.
5.5 Storage Virtualisation on Block or File Level.
5.6 Storage Virtualisation on Various Levels of the Storage Network.
5.6.1 Storage virtualisation in the server.
5.6.2 Storage virtualisation in storage devices.
5.6.3 Storage virtualisation in the network.
5.7 Symmetric and Asymmetric Storage Virtualisation in the Network.
5.7.1 Symmetric storage virtualisation.
5.7.2 Asymmetric storage virtualisation.
PART II Application and Management of Storage Networks.
6 Application of Storage Networks.
6.1 Definition of the Term ‘Storage Network’.
6.1.1 Layering of the transmission techniques and protocols.
6.1.2 Networks in the I/O path.
6.1.3 Data networks, voice networks and storage networks.
6.2 Storage Sharing.
6.2.1 Disk storage pooling.
6.2.2 Dynamic tape library sharing.
6.2.3 Data sharing.
6.3 Availability of Data.
6.3.1 Failure of an I/O bus.
6.3.2 Failure of a server.
6.3.3 Failure of a disk subsystem.
6.3.4 Failure of virtualisation in the storage network.
6.3.5 Failure of a data centre based upon the case study ‘protection of an important database’.
6.4 Adaptability and Scalability of IT Systems.
6.4.1 Clustering for load distribution.
6.4.2 Web architecture.
6.4.3 Web applications based upon the case study ‘travel portal’.
7 Network Backup.
7.1 General Conditions for Backup.
7.2 Network Backup Services.
7.3 Components of Backup Servers.
7.3.1 Job scheduler.
7.3.2 Error handler.
7.3.3 Metadata database.
7.3.4 Media manager.
7.4 Backup Clients.
7.5 Performance Gains as a Result of Network Backup.
7.6 Performance Bottlenecks of Network Backup.
7.6.1 Application-specific performance bottlenecks.
7.6.2 Performance bottlenecks due to server-centric IT architecture.
7.7 Limited Opportunities for Increasing Performance.
7.7.1 Separate LAN for network backup.
7.7.2 Multiple backup servers.
7.7.3 Backup server and application server on the same physical computer.
7.8 Next Generation Backup.
7.8.1 Server-free backup.
7.8.2 LAN-free backup.
7.8.3 LAN-free backup with shared disk file systems.
7.8.4 Backup using instant copies.
7.8.5 Data protection using remote mirroring.
7.8.6 Tape library sharing.
7.9 Backup of File Systems.
7.9.1 Backup of file servers.
7.9.2 Backup of file systems.
7.9.3 Backup of NAS servers.
7.9.4 The Network Data Management Protocol (NDMP).
7.10 Backup of Databases.
7.10.1 Functioning of database systems.
7.10.2 Classical backup of databases.
7.10.3 Next generation backup of databases.
7.11 Organisational Aspects of Backup.
8.1.1 Differentiating between information and data.
8.1.3 Digital archiving.
8.1.4 Reference architecture for digital archive systems.
8.1.5 Differentiating between archiving and backup.
8.1.6 Differentiating between archiving and ILM.
8.2 Motivation, Conditions and Requirements.
8.2.1 Reasons for archiving.
8.2.2 Legal requirements.
8.2.3 Technical progress.
8.2.4 Requirement for stability.
8.2.5 Risks from the environment and from society.
8.2.6 Requirement for adaptability and scalability.
8.2.7 Operational requirements.
8.2.8 Cost-related requirements.
8.2.9 Conclusion: Archive systems as a strategic investment.
8.3 Implementation Considerations.
8.3.1 WORM storage technologies.
8.3.2 Data security.
8.3.3 Data integrity.
8.3.4 Proof of regulatory compliance.
8.3.5 Deletion of data.
8.3.6 Continuous operation.
8.3.7 Loss-free operation.
8.3.8 Data management: storage hierarchy and migration.
8.3.9 Component-neutral archiving.
8.3.10 Selection of components and vendors.
8.4 Interfaces in Archive Systems.
8.4.1 Interface between application and DMS.
8.4.2 Java Content Repository (JCR).
8.4.3 Interface between DMS and archive storage.
8.4.4 eXtensible Access Method (XAM).
8.4.5 Management interfaces.
8.4.6 Interface between DMS systems.
8.4.7 Standardised interfaces for archive systems.
8.5 Archive Solutions.
8.5.1 Archiving of emails.
8.5.2 Archiving of files.
8.5.3 Archiving of ERP systems.
8.5.4 Archiving in hospitals.
8.5.5 Central archives.
8.6 Operational and Organisational Aspects.
8.7 Summary and Outlook.
9 Business Continuity.
9.1 General Conditions.
9.1.2 Target audience.
9.1.3 Classification of risks.
9.1.4 Classification of outages.
9.1.5 IT failures in the context of business processes.
9.1.6 Resumption of business processes.
9.1.7 Business continuity for the web architecture.
9.1.8 Cost optimisation for business continuity.
9.1.9 Risk analysis and risk management.
9.1.10 Creation of a business continuity plan.
9.2 Strategies of Business Continuity.
9.2.1 High availability.
9.2.2 Disaster recovery.
9.2.3 Continuous business operation.
9.3 Parameters of Business Continuity.
9.3.2 Characterisation of availability (MTBF, MTTR and MTTF).
9.3.3 Calculation of overall availability.
9.3.4 Characterisation of failures (RTO and RPO).
9.3.5 Network Recovery Objective (NRO).
9.4 Quality of Service for Business Continuity.
9.4.1 Service Level Agreements (SLAs).
9.4.2 High availability versus disaster recovery.
9.4.3 The seven-tier model.
9.4.4 Tier 0: no data backup.
9.4.5 Tier 1: data backup without a backup data centre.
9.4.6 Tier 2: data backup with backup data centre.
9.4.7 Tier 3: electronic vaulting.
9.4.8 Tier 4: instant copies.
9.4.9 Tier 5: software mirroring.
9.4.10 Tier 6: disk subsystem-based mirroring.
9.4.11 Tier 7: fully automated solutions.
9.5 Business Continuity Solutions.
9.5.1 Basic techniques.
9.5.2 Solution segments of the seven-tier model.
9.5.3 Backup and restore.
9.5.4 Rapid data recovery using copies.
9.5.5 Rapid data recovery using mirrors.
9.5.6 Continuous availability.
9.6 Switch of Operational Location.
9.7 Organisational Aspects.
10. Management of Storage Networks.
10.1.1 User-related requirements.
10.1.2 Component-related requirements.
10.1.3 Architectural requirements.
10.1.4 One central management system.
10.1.5 Five basic services.
10.2 Characterisation of Management Interfaces.
10.2.1 In-band interfaces.
10.2.2 Out-band interfaces.
10.2.3 Standardised interfaces.
10.2.4 Proprietary interfaces.
10.3 In-band Management.
10.3.1 In-band management in Fibre Channel SAN.
10.4 Out-band Management.
10.4.1 The Simple Network Management Protocol (SNMP).
10.4.2 CIM and WBEM.
10.4.3 Storage Management Initiative Specification (SMI-S).
10.4.4 CMIP and DMI.
10.5 Operational Aspects of the Management of Storage Networks.
11 Removable Media Management.
11.1 The Significance of Removable Media.
11.2 Removable Media.
11.2.2 CD, DVD and magneto-optical media.
11.2.3 Management features of removable media.
11.3 Libraries and Drives.
11.3.3 Media changers.
11.4 Problems and Requirements in Respect of Removable Media Management.
11.4.1 Efficient use of the available resources.
11.4.2 Access control.
11.4.3 Access synchronisation.
11.4.4 Access prioritisation and mount request queuing.
11.4.5 Grouping, pooling.
11.4.6 Media tracking and vaulting.
11.4.7 Cartridge life cycle management.
11.5 The IEEE 1244 Standard for Removable Media Management.
11.5.1 Media management system architecture.
11.5.2 Media manager and MMP.
11.5.3 Library manager and drive manager.
12 The SNIA Shared Storage Model.
12.1 The Model.
12.1.1 The functional approach.
12.1.2 Graphical representations.
12.1.3 An elementary overview.
12.1.4 The components.
12.1.5 The layers.
12.1.6 The file/record layer.
12.1.7 The block layer.
12.1.8 Combination of the block and file/record layers.
12.1.9 Access paths.
12.1.11 Access control.
12.1.13 Storage, data and information.
12.1.14 Resource and data sharing.
12.1.15 The service subsystem.
12.2 Examples of Disk-Based Storage Architectures.
12.2.1 Direct attached block storage.
12.2.2 Storage network attached block storage.
12.2.3 Block storage aggregation in a storage device: SAN appliance.
12.2.4 Network attached block storage with metadata server: asymmetric block services.
12.2.5 Multi-site block storage.
12.2.6 File server.
12.2.7 File server controller: NAS heads.
12.2.8 Asymmetric file services: NAS/file server metadata manager.
12.2.9 Object-based storage device (OSD).
12.3 Extension of the SNIA Shared Storage Model to Tape Functions.
12.3.1 Logical and physical structure of tapes.
12.3.2 Differences between disk and tape.
12.3.3 Extension of the model.
12.4 Examples of Tape-Based Backup Techniques and Architectures.
12.4.1 File backup.
12.4.2 File system volume backup.
12.4.3 Volume backup.
12.4.4 File backup to virtual tape.
12.4.5 Direct attached tape.
12.4.6 LAN attached tape.
12.4.7 Shared tape drive.
12.4.8 Partitioned tape library.
12.4.9 Virtual tape controller.
12.4.10 Virtual tape controller with disk cache.
12.4.11 Data mover for tape.
12.4.12 File server with tape drive.
12.4.13 File server with external tape.
12.4.14 File server with data mover.
13 Final Note.
Appendix A: Proof of Calculation of the Parity Block of RAID 4 and 5.
Appendix B: Checklist for the Management of Storage Networks.
B.1.5 Efficient use.
B.2.3 Data protection.
B.2.6 Data sharing.
B.2.7 Security/access control.
B.3.1 Inventory/asset management and planning.
B.3.4 Resource use.
B.3.6 Efficient resource utilisation.
B.3.8 Resource migration.
Ulf Troppens (centre) studied Computer Science at the University of Karlsruhe. Since 1989 he has been primarily involved in the development and administration of Unix systems, storage systems, data and storage networks and distributed applications.
Rainer Erkens (left) studied Mathematics at the University of Mainz. His experience in the management of computers and distributed applications goes back to 1992. Since 2005 he is a technical support manager in IBM’s European Storage Competence Center.
Wolfgang M¨ uller-Friedt (right) studied Computer Science at the FH Darmstadt. He is a software architect focussing on the software development of management applications for storage networks which support open standards such as SMI-S and IEEE 1244.
Nils Haustein (left front) studied Electrical Engineering at the TU Chemnitz. For several years he is with IBM’s advanced technical sales support in Europe where he is focussing on digital archiving.
Rainer Wolafka (right front) studied Electrical Engineering at the FH Frankfurt and Software Engineering at the Santa Clara University. Since 1997 he is working in the field of storage networks and the software development of management applications for storage networks.