Internetworking the Storage Area Networks

STANISLAV MILANOVIC *), NIKOS E. MASTORAKIS **)

*) Highest Institute of Education, Science and Technology Haghiou I. Theologou 17 15773, Zographou, Athens, GREECE

**) MILITARY INSTITUTIONS OF UNIVERSITY EDUCATION HELLENIC NAVAL ACADEMY Terma Hatzikyriakou, 18539, Piraeus, GREECE.

Abstract: - A SAN internetworking has been meet the high-availability, high-performance highlighted in this describing new requirements of today’s most demanding e- technologies available for building an business applications. SAN is focused on the single enterprise-wide SAN and connecting task of managing storage resources and removing SANs over (WAN). The new that task from the LAN or servers. SANs storage-centric infrastructure includes an open, accomplish this by providing any--to-any- modular and scalable storage network, not tied to storage connectivity through the use of Fibre any one server or application. Channel switch fabric technology. From a client network perspective, the SAN environment Key-Words: - , Fibre complements the ongoing advancements in LAN Channel, e-business, WAN, , ATM, Gigabit () and WAN (Wide Area Network) technologies [1, 2, 3, 4, 5, 6, 7, 8] by extending the benefits of improved performance 1 Introduction and capabilities all the way from the client and Companies across all industries are launching new backbone through to servers and storage. SANs are business-critical applications such as enterprise currently used to connect shared storage arrays, resource planning, business intelligence, customer cluster servers for failover, interconnect mainframe relationship management and supply chain disk or tape resources to distributed network reengineering — turning information into a servers and clients, and create parallel or alternate strategic corporate asset. With information taking data paths for high performance computing center stage as a competitive differentiator, storage environments [9]. Most SAN solution vendors also has moved from supporting player to a leading role mandate SNMP (Simple Network Management in a company’s IT strategy and budget. Protocol) support for all the SAN networking components, which is then used and exploited by To remain successful in such a dynamic SNMP based network management applications to marketplace, organizations need reliable storage report on the various disciplines of SAN systems that can effectively manage and protect management [10]. critical business information. These systems must be able to scale quickly to manage anticipated data The central foundation of the SAN is Fibre Channel growth — a difficult problem for many traditional technology (FC). The first generation SAN storage approaches. As a result, organizations are provides 1Gb/s (2Gb/s full-duplex), while the now accessing and managing the ever-increasing second generation SAN supports multiple data rates amount of enterprise data through innovative up to 2Gb/s (4 Gb/s full-duplex) [11]. The FC Storage Area Networks (SANs). specification is a set of standards being developed by ANSI (American National Standards Institute) and is ideal for storage, video, graphic and mass 2 SAN Technology Overview data transfer applications [12]. FC is a layer 2 SAN is a separate, centrally managed (but technology which operates over copper and fiber functionally distributed) networked environment optic cabling with maximum distances appropriate that provides a scalable, reliable IT infrastructure to to the media (30m for copper, 500m for short-wave laser over multimode fiber, 10Km for long-wave • Enhanced performance laser over single mode fiber) [13]. FC supports Take storage traffic off the enterprise LAN and protocols such as SCSI (SCSI over FC is called enterprise servers. The SAN enables bulk data FCP), ESCON (Enterprise Systems Connection), transfer from each server to shared SAN storage, FICON (Fiber Connectivity), SSA (Serial Storage but the LAN is used only for communication (not Architecture), IPI (Intelligent Peripheral Interface), data) traffic between the servers. Sophisticated HiPPI (High Performance Parallel Interface), and recovery software applications still ATM, IP [14]. FC is designed to transport large control the process, tracking the backup and blocks of data with greater efficiency and reliability recovery data. The result is a faster, more scalable, than IP-based networks, which can significantly and more reliable backup and recovery solution — improve backup and recovery performance. FC with more effective utilization of storage, server, supports three topologies: point-to-point, arbitrated and LAN resources [17]. loop (FC-AL), and switched — FC-SW (1Gb/s, • Mission continuity i.e. 2Gb/s full duplex) or FC-SW2 (2Gb/s, - Consolidate and archives i.e. 4Gb/s full duplex); all three topologies are fully - Disk mirroring to disaster recovery sites interoperable, so the topology is transparent to the • Applications attached devices. The principal change in this new - High availability mission critical databases architecture is the externalization of server storage - Distributed server clustering onto the SAN as a shared resource attached to - Disk virtualisation multiple servers [15] (Figure 1). It does not matter whether the attached storage resources are mainframe DASD (direct access storage device), 4 Requirements open systems disk arrays, or even remote storage Since standards from SNIA (Storage Network used for a variety of reasons. They are all Industry Alliance) and the FCIA (Fibre Channel connected by a SAN utilizing high-speed storage Industry Alliance) are just now coming into being, interconnect technologies. the major requirement was to deploy FC switches whose firmwares were upgradeable to newer versions as new standards become available.

Specific requirements that were driving towards storage area networking solution include: • Scalability, • High Speed Storage Access, • Heterogeneous connectivity, • Flexibility in Server and Storage Placement, • Secure transactions and data transfer, • 24x7 response and availability.

Figure 1. The SAN 5 SAN Internetworking The LAN meets the SAN at the server. The server Following are network components that had been is provisioned with both a LAN interface card and employed to build and interconnect an a FC Host Bus Adapter (HBA). As a user requests enterprise-wide SAN infrastructure: data from the server over the LAN, the server • SilkWorm 3800 switch (SW3800) provides 16 retrieves the data from storage over the SAN [16]. ports with auto-sensing 1Gbit/s (2Gb/s full SANs are relatively complex structures that marry duplex) and 2Gbit/s (4Gb/s full duplex) networking, storage and data management interfaces for seamless integration with existing technologies and techniques. FC fabrics. SW3800 includes Brocade Advanced Fabric Services that increase security through hardware-enforced World 3 Objective Wide Name zoning [18]. SW3800 switches The commitment was to providing an open, were deployed with fiber optic cabling to vendor-neutral SAN solution to meet the following support all FC-related topologies providing objectives: reliable, high-performance data transfer that is critical to efficient SAN applications, such as LAN-free backup, server-free backup, storage • Tivoli Storage Manager (TSM) server running consolidation, remote mirroring and on AIX. TSM delivers data protection for file high-availability clustering configurations. and application data, record retention, space Inter-switched links (ISLs) trunking create a management, and disaster recovery. The client 4Gb/s (8Gb/s full duplex) data path between software (Storage Agent) running on different two central SW3800 switches (Figure 2) for systems (PCs, workstations or application higher performance. servers), in conjunction with the server • The ATTO FibreBridge 4500C/R/D Fibre software (TSM) enables the LAN-free data Channel-to-SCSI bridge is configured with transfer exploiting SAN infrastructure [20]. three independent Fibre Channel ports and four • The ADVA DiskLink SAN Interconnect independent Ultra2 SCSI buses [19]. Gateway enables the distribution and mirroring • Compaq ProLiant (Windows NT/2000, Linux), of data across multiple sites. DiskLink is a IBM RS6000 (AIX), HP9000 (HP-UX), Sun high-performance storage networking device Enterprise (Solaris) servers; IBM Enterprise that provides 2Gb/s Fibre Channel (4Gb/s full Storage Server 2105 F20 RAID (Redundant duplex) and Ultra 2 SCSI networking over Array of Independent Disks), Nextor 18F (FC unlimited distances across ATM networks at target JBOD - Just a Bunch of Disks); 155/622 Mbps, or over next-generation Internet Terasystem DataSTORE LTO TLS 8000 (FC services (Virtual Private Networks) with or SCSI tape library); Terasystem OptiNET Gigabit Ethernet. Configurable levels of CD-ROM/DVD Jukebox and CD-ROM/DVD intelligent storage command handling allow Jukebox Controller; Adaptek 2940U2W DiskLink to reduce the impact of transmission (Ultra2 SCSI adapters); FC 6227, 2100 delays and eliminate distance barriers [21]. and 2200 series Fibre Channel HBAs.

Figure 2. Local SAN island deployment at Italian corporate headquarter

Native FC technology provides the 10 km or backup and disaster recovery plans while utilizing greater link extended distance connectivity required the existing storage facilities and network to maintain geographically separate disaster infrastructure [23]. Figure 3 shows a deployed recovery facilities or mirroring operations. enterprise-wide SAN solution spanning European Nevertheless, remote switches can provide virtually sites of a well-known international organization. In unlimited distance connections through the ATM this scenario, the storage devices appear logically protocol over existing WAN [22]. This SAN as if they were on the same bus or loop, but gain interconnectivity allows a prominent the advantages of a switched infrastructure. The communications provider to implement remote ATM network sets up direct paths between devices and becomes a Virtual SAN switch — a Virtual located anywhere [24]. The V-SAN facilitates SAN (V-SAN). The V-SAN is distance remote archiving, disaster recovery, web caching independent while storage and servers can be and data warehousing (multi-site, central storage).

Figure 3. Internetworked Storage Area Networks

6 Conclusion SANs generate considerable interest in the In addition to the fundamental connectivity computer industry because, in this age of explosive benefits, deployed enterprise-wide SAN also growth in storage needs and the resulting features the new capabilities, facilitated by its complexity in managing storage, SANs provide a networking approach, which enhances SAN's value viable solution, managing a company's current as a long term infrastructure. These capabilities, storage needs, as well as its future growth. which include compute clustering, topological flexibility, fault tolerance, high availability and References: remote management, further elevate deployed [1] Stanislav Milanovic, Nikos E. Mastorakis, SAN's ability to address the growing challenges of “Delivering Enhanced Voice Services over the data-intensive, mission-critical e-business Internet”, WSEAS TRANSACTIONS on SYSTEMS, applications. Issue 1, Volume 1, pp. 74-80, January 2002, WSEAS Press, http://www.wseas.org. 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