In an effort to continue to improve business productivity and customer service, most organizations are deploying data intensive enterprise applications like customer relationship management (CRM), enterprise resource planning (ERP), and e-mail. This has resulted in an explosion of information and data that has become the lifeblood of these organizations, greatly elevating the importance of a sound storage strategy. Selecting a unified architecture that integrates the appropriate technologies to meet user requirements across a range of applications is central to ensuring storage support for mission critical applications. Matching technologies to user demands allows for an optimized storage architecture, providing the best use of capital and IT resources.

Storage area networks (SAN) have emerged as the best solution for advanced storage requirements. Often, SANs can alleviate many if not all of the pain points of IT managers, since they allow for more manageable, scalable, and efficient deployment of mission-critical data. Not only do SANs provide advanced functionality, but they also lower an organization's total cost of ownership (TCO) and provide significant positive return on investment (RoI) versus a direct attached storage (DAS) environment.

Not all SAN technologies are the same. However, in order to realize the positive benefits of SAN deployment, the choice of vendor and SAN implementation partner is just as critical as the SAN equipment itself. Centralized, efficient management, intelligent SAN services, a truly robust and flexible platform and global, 24x7 service and support are requisites for next-generation SAN technologies. Any solution that closes off heterogeneous options-whether it is protocol-, vendor-, or equipment-specific-will only be a transient solution with limited strategic and RoI justification. The optimal SAN solution will have a robust, high-performance architecture that creates new opportunities and alternatives while protecting resource investments from unexpected turns in the economic environment and changes in market adoption of new technology.

An IT Manager's Dilemma
IT managers across three states in the US identified the following five major 'pain points' when asked about their storage management.

• Difficulty of managing large, disparate islands of storage from multiple physical and virtual locations.
• Complexity of maintaining scheduled backups for multiple systems and difficulty in preparing for unscheduled system outages.
• Inability to share storage resources and achieve efficient levels of subsystem utilization.
• Shortage of qualified storage professionals to manage storage resources effectively.
• Confusion over the justification of a plethora of storage technology alternatives, including appropriate deployment of fiber channel, Internet small computer systems interface (iSCSI), fibre channel over IP (FCIP), and InfiniBand. To add to these technical dilemmas, IT managers are facing restricted budgets and increasing costs of deploying and maintaining both DAS and SANs, despite decreasing prices for physical storage in terms of average street price (ASP) per terabyte. The result, that IT projects are faced with a greater of scrutiny than ever before.

However, regardless of the economic environment and the abundance of new technologies, organizations must continue to invest in IT projects that support specific business goals and that can produce quick RoIs. A well-planned, well-justified storage strategy will allow a business to emerge from adverse market conditions in a better position to take advantage of new opportunities. In effect, the choice of storage investment can actually result in a sustainable competitive advantage versus the competition. For example, a brokerage firm that loses the ability to commit transactions during trading hours will suffer significant losses relative to a competitor.

A large consumer goods retailer that can't determine its inventory in real time because of insufficient storage will suffer higher costs than a competitor that has implemented storage provisioning and management tools that can track inventory flows and store all relevant data in an easy-to-access database.

It is important, therefore, that the decision makers in the storage strategy include not only technical IT managers, but also business and financial managers who want a greater strategic and financial justification in order to invest the organization's capital.

Evolution and Benefits of Networked Storage
The evolution of SAN has progressed to the point where all organizations should seriously evaluate their role in the future of their storage environment. According to a recent report from Gartner Dataquest, the market for SAN-attached external storage in 2005 will exceed $22 billion, representing almost three million terabytes of data.

The main reason SANs have emerged as the leading advanced storage option is because they often can alleviate many if not all of the pain points of IT managers. They allow for more manageable, scalable, and efficient deployment of mission-critical data.

A large number of enterprises have already tested or implemented production SANs and many industry analysts have researched the actual benefits of these implementations. A study of large enterprise data center managers by Gartner andWitSoundview shows that 64 percent of those surveyed were either running or deploying SANs. Another study by the Aberdeen Group cites that nearly 60 percent of organizations that have a SAN installed have two or more separate SANs. The study also states that 80 percent of those surveyed felt that they had satisfactorily achieved their main goals for implementing a SAN. Across the board, all vendor case studies and all industry analyst investigations have found the following benefits of SAN implementation when compared to a DAS environment: ease of management, increased sub-system utilization, reduction in backup expense, and lower TCO.

Business Impact of Current SANs
IT managers perceive the benefits of a centralized point of management since it makes the everyday work of storage administrators easier. But, to truly justify a SAN investment from both a technical and a business perspective, it is necessary to attach concrete savings in money terms to the benefit or to define a concrete source of competitive advantage. While the hard cost savings are usually enough to justify migrating to a SAN, the less-easily quantifiable 'soft benefits' may provide the most compelling argument.

A good IT investment (and, therefore, a good networked storage architecture) should lead to a lower TCO and a higher RoI. In this paper, TCO refers to the full cost of a project including upfront capital costs and recurring costs over the period of the project (two years, three years, etc.), and RoI is the average expected cash flow over the period of the project divided by the initial investment outlay.

There are three major quantifiable savings associated with SANs that lower TCO and result in a large positive RoI versus DAS environment: reduced management costs, reduced sub-system costs, and reduced backup costs. There are also two more strategic benefits of SANs that, though difficult to quantify, may be even more important justifications for SAN implementation: high availability and disaster recovery.

Management Costs
A study by McKinsey and Merrill Lynch shows that the TCO of SAN solutions typically is less than half that of DAS solutions primarily because of huge savings in management costs. The study found that SANs were able to lower the budget for storage administrators from 47 percent of total cost to less than 10 percent.

The main reason for the cost savings is that SANs are easier to manage than DAS because of the existence of a simplified, central point of control for monitoring, backup, replication, and provisioning. This results in an increased amount of TB of data that a single storage administrator can manage. This frees up time for administrators to devote to more value-added activities. This time saving results in slower staff growth and ultimately decreases the required rate of hiring.

Sub-system Costs
SANs allow any-to-any access and connectivity between storage and servers. Therefore, servers can be better matched with underutilized sub-systems and overall capacity utilization can increase. This leads to savings on future sub-system purchases as less disks need to be added each year. For example, in DAS environments it is usually possible to achieve 50 percent capacity utilization of usable data storage space. So, if an organization has 20 TB of data to store, it will actually have to purchase 40 TB of disk. Current SANs can increase utilization to about 70–85 percent. The same organization would only need 24–29 TB of disk in this scenario. The difference in storage utilization can add up quickly in a fast-growing organization.

Scalability
Compared to physically separated SANs, VSANs (virtual SANs) offer much greater flexibility. Moving a device from one VSAN to another requires only configuration at the port level, rather than a physical move. Compared to zoning, VSANs provide a more complete mechanism for traffic isolation by enforcing control of frames at every step along the way, rather than only at the edge of the fabric.

This partitioning of fabric services greatly reduces network instability by containing fabric reconfigurations and error conditions within an individual VSAN. Should a fabric function such as fabric shortest path first (FSPF) have a failure, the failure is contained to the VSAN and has no effect on the rest of the switch. VSANs also provide the same isolation between individual VSANs as would exist between physically separated SANs. Traffic cannot cross VSAN boundaries and devices may not reside in more than one VSAN. This attribute of VSANs is of great value in service provider environments where absolute separation must be maintained between customers. Since VSANs each run separate instances of fabric services, each VSAN has its own zone server, name server, and FSPF and can be zoned in exactly the same way in which SANs without VSAN capability are zoned.

VSANs save customers money by enabling them to consolidate physically separate switch infrastructures that may not have optimal port utilization into one physical infrastructure that can be managed as a single logical entity. Not only is this one infrastructure easier to manage, but in general it will have fewer ports.

Excerpted from a Cisco white paper

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