Why Invest in SAN ?

Slide Presentation

During the past eight or ten years, businesses have experienced unprecedented growth, making national and even global entities out of many companies. Growing markets, mergers, and acquisitions fueled the growth and continue to do so. These changes have pressed existing IT architectures to their limits and thrown dissimilar and incompatible systems together in far-flung business enterprises. The result is an IT manager’s nightmare, particularly as it relates to data storage, movement, and protection within the resulting enterprise networks.

Existing models, or paradigms, are inadequate to handle the simultaneous explosion and isolation of data in such enterprise systems. The tremendous growth of data and the need to integrate corporate IT structures into cohesive enterprise-wide systems are literally overwhelming today’s system architectures. The storage area network, or SAN, is emerging at the core of new technologies and models which promise to resolve many of the key issues in these diverse environments and help link heterogeneous systems into cohesive enterprise networks.

Bob Weisickle, Chairman of the Board of Directors of the Fibre Channel Association (FCA) recognized the emerging role of SANs at the FCA Wall Street Conference in December 1998, where he said: “Paradigms and technologies are changing the IT environment. New technologies and paradigms that are being deployed center on the promise of the SAN.Wide area SANs with global distribution must be supported...”

The SAN is a concept whose time has arrived, and dealing with SANs over wide areas is inevitable.

LAN Growth and The Genesis of SANs

What are the needs that make SANs viable solutions, and how did those needs arise?

SANs are a response to needs resulting from the growth of local area networks, or LANs. The growth of a LAN is merely a reflection of the growth of the business or company it serves. If company growth were one-dimensional—attributable only to market growth for example—LAN growth could be more planned and perhaps even homogeneous in nature. The LAN would extend to nearby locales to form a campus. It may then spread to locations more distant but still within the same metropolitan area, forming a metropolitan area network or MAN. Eventually, it would extend to wider areas outside the metropolitan area, requiring some form of long distance service. The resulting wide area networks, or WANs, can be national or even international in scope.

However, corporate growth rarely occurs in easily manageable chunks over reasonable periods of time. Rather, it often is abrupt and almost “eye-popping” in scope, resulting in instantaneous diversity and incompatibilities that restrict access and impact network management and performance.

Mergers and acquisitions, for example, contribute much of the growth that many companies experience today. More often than not, diversity accompanies that growth, including servers using different operating systems and storage devices with different interface protocols. The chances of LANs developed by different organizations being the same are highly unlikely. This often even applies to LANs developed by different divisions within the same company. In addition, LAN technologies change quite rapidly. Even if the next phase of a LAN were developed by the same organizations, they would use the latest technology with or without upgrading older elements (depending on budget considerations).

Growth, particularly growth due to mergers of independently developed organizations, also tends to introduce networking complexities and inefficiencies. In most LANs, storage devices are connected to a single server. When two or more LANs are merged, storage within those LANs remains dedicated to the specific servers to which they are attached. This leads to “islands of information,” which are difficult to manage and inefficient to maintain and upgrade.

Growth can give rise to conflicting IT needs, which impact network performance. Recent estimates show that the data in use by healthy growing companies tends to at least double annually. At the same time, the demand by users for access to application data is steadily approaching the 24 x 7 mark (24 hours per day, 7 days per week). Increasing data traffic on the network absorbs more network resources and can degrade network application performance. The increased volumes of data involved in normal maintenance, such as backup and restore, take longer to move in the network and are impacted by increasingly shorter windows of time available for such operations to execute.

SANs represent a new model, or paradigm, to apply to solutions to address these issues.

The Benefits of a SAN

A SAN is a high-speed network within a network. It is focused on the single task of managing storage resources and removing that task from the LAN it occupies. It has many compelling benefits that can alleviate the problems inherent in the growth of LANs.

[Illustration 1 (attached): “Why Invest in SAN?” ( Slide #9) from the “CNT SAN Works” Presentation]

A primary benefit of a SAN is data access. A SAN allows any server to physically access any storage unit within the SAN (“any to any” access). This breaks the “islands of information” barrier and allows applications to be consolidated within the network and physical storage to be used more fully.

A SAN is fast, making it possible to move high volumes of data quickly and more efficiently within the network. This is particularly important with the exponential growth of data volumes and progressive decrease in the windows of time available to handle routine maintenance operations.

SANs often handle conversions among widely different storage protocols (e.g., Fibre Channel, SCSI, and ESCON). Fibre Channel is a highly reliable, gigabit interconnect technology that allows fast simultaneous communication among network components. Despite its cost, it is the choice of many new implementations today. SCSI is a well entrenched PC storage protocol. Many companies have significant investments in SCSI-based storage devices they want to protect. ESCON is the most common protocol for access to mainframe-based legacy applications. Access to legacy applications for many companies is an important requirement for their open systems networks.

A good SAN will also handle different servers in the network, for example Microsoft NT and UNIX. The very nature of corporate growth often creates networks with combinations of different operating systems, either from developments of different divisions of the company or from mergers and acquisitions of other companies. The SAN must be adept at interfacing with all commonly used systems.

Once storage is “pooled” in a SAN, storage devices can be accessed equally by all servers in the network and used more fully. If a new company is acquired, for example, that company’s storage devices can be incorporated into the SAN and its applications consolidated with existing network applications, rather than trying to maintain separate implementations of the same applications and storage devices.

Because common protocols are accepted and integrated, there is no need to discard or replace perfectly serviceable storage units simply because they are not the “right” protocol. SANs integrate the old with the new, preserving a company’s current storage investment and simplifying the whole expansion and upgrade process.

The Importance and Impact of WAN Connections

Most successful companies will at some time or another require WAN connections. Such requirements may start rather modestly to include for example a remote account manager or consultant who needs network access. It generally progresses to encompass whole groups, departments, or even divisions. The whole process can expedite rather quickly when company mergers or acquisitions become involved.

WAN connections present an entirely new set of networking issues, many of which are geared around access. To begin with, access involves telecommunications rather than simply running a cable to someone’s office. Telecommunications in turn involves long distance communication service. And, long distance service tends to be expensive and can sometimes be unreliable. Fixing problems requires relying on outside persons or groups, which increases risks of extended periods of service interruption.

Speed and capacity are other WAN issues of concern. Servers and workstations in LANs are cabled directly to one another. The connections are simple, and the speed is fast (10 megabits per second or more). Telecommunications connections are complex (dedicated lines, switched lines, T-1 service, etc.) and are generally routed through multiple public facilities. Telecommunications speed and capacity are also more restrictive (1.544 megabits per second down to 56 kilobits per second, for example). LAN speeds can be as much as a magnitude or two faster than telecommunications speeds. “Bandwidth” use (how fully the available capacity of the long distance carrier is used) is an important concern.

All of this adds complexity to SANs. Therefore, SANs in this case must include good long distance capabilities, including the ability to extend device channel connections over long distances, reroute communications quickly and efficiently if a particular link goes down, and include techniques for using the available bandwidth efficiently.

A good SAN will include network management capabilities such as alternate pathing, load leveling, and data compression, most often as a complement to cross-connections that provide multiple paths in the network. Together, these facilities provide alternative routes in case of heavy traffic or blockages that would stop or delay data transmission and well developed methodologies for compressing and prioritizing data to maximize speed through the network.

[Illustration 2 (attached): “SAN Network Intelligence” Slide from “CNT SAN Works” Presentation]

SAN Over WAN Applications

SANs with WAN connections appear to be most in demand for backup and restore, disk mirroring, and data sharing applications in today’s IT environments.

The first two are data protection applications, which are of paramount importance to most successful companies today. Most companies can ill-afford even minimal downtime. With the volumes of data increasing exponentially and the windows of time to execute normal maintenance and backup and restore operations dwindling drastically, a revolutionary data handling facility, such as a SAN, is necessary to move large data files without degrading network performance.

[Illustration 3 (attached): “Multi-Server Backup at a Major Financial Institution” Slide from “CNT SAN Works” Presentation]

SANs are extremely good at moving large volumes of data with no impact to normal LAN processing. With today’s SAN technology, such maintenance operations can be interwoven or even done simultaneously with normal production operations. In a WAN, backup or mirrored data can be stored remotely for complete disaster protection, with the capabilities to restore the original data or reroute the data to other processors in case of emergencies. The net result is to minimize the affect of an emergency or disaster and the resulting downtime. This is particularly important as a company moves toward 24 x 7 service provisions to its customers.

[Illustration 4 (attached): “Remote Disk Mirroring at SWISSCOM Mobile” Slide from “CNT SAN Works” Presentation]

Mainframe legacy systems often contain extensive databases of customer demographic and other business data collected from day-to-day business operations. Many companies make that data available to open system servers (UNIX or Window NT) for analysis and reporting as part of a data warehousing operation. SANs are a natural vehicle for such data sharing because of their ability to bridge between diverse systems and overcome the problems of distance, speed, and heterogeneity. Data sharing may also be an important tool for consolidating applications within an enterprise, with multiple locations sharing the same database.

Partnerships and SAN Solution Testing

SANs over WANs are complex structures, involving networking, storage, and data management disciplines, which has led to cooperative relationships among hardware, software, and network service providers. Companies today, even those with limited SAN/WAN expertise, have a wealth of equipment, software, and services to choose from in developing and maintaining SANs for both local and wide area use. Reputable networking and storage system developers like Computer Network Technology, EMC Corporation, STK Technologies, SCH Technologies and others are working together to take advantage of the SANs market opportunity. Many have extensive certification and testing processes for ensuring that the products and solutions from different manufacturers work properly and reliably with their own. Some even offer consulting services to help their customers plan and implement networking solutions.

SANs are a good idea whose time has come. They represent a new paradigm, or model, that can serve as an effective core of solutions to meet the needs of today’s emerging enterprise networks.