Direct Attached Storage, Network Attached Storage or Storage Area Network?

Data is unquestionably the lifeblood of business and organizations of all sizes. Storage solutions remain a top priority in IT budgets precisely because the integrity, availability and protection of data are vital to business productivity and success but the role of information storage far exceeds day to day functions. Enterprises are also operating in an era of increased uncertainty. IT personnel find themselves assessing and planning for more potential risks than ever before, ranging from acts of terrorism to network security threats. A backup and disaster recovery plan is essential, and information storage solutions provide the basis for its execution.

Businesses are also subject to a new wave of regulatory compliance legislation that directly affects the process of storing, managing and archiving data. This is especially true for the financial services and healthcare industries, which handle highly sensitive information and bear extra responsibility for maintaining data integrity and privacy.

Although the need for storage is evident, it is not always clear which solution is right for your business or organization. There are a variety of options available, the most prevalent being direct attached storage (DAS), network attached storage (NAS) and storage area networks (SAN). There is no one right answer for everyone. Instead, it is important to focus on the specific needs and long term business goals of your organization.

While one type of storage media is usually sufficient for smaller companies, medium and large enterprises will often have a mixed storage environment, implementing different mediums for specific departments, workgroups and remote offices. Below is an overview of DAS, NAS and SAN to help you determine which solution or combination of solutions will best help you achieve your business goals.

Direct Attached Storage
(DAS)

Ideal for Local Data Sharing Requirements

Direct attached storage, or DAS, is the most basic level of storage, in which storage devices are part of the host computer, as with drives, or directly connected to a single server, as with RAID arrays or tape libraries. Network workstations must therefore access the server in order to connect to the storage device. As the first widely popular storage model, DAS products still comprise a large majority of the installed base of storage systems in today's IT infrastructures.

Although the implementation of networked storage is growing at a faster rate than that of direct attached storage, it is still a viable option by virtue of being simple to deploy and having a lower initial cost when compared to networked storage. When considering DAS, it is important to know what your data availability requirements are. In order for clients on the network to access the storage device in the DAS model, they must be able to access the server it is connected to. If the server is down or experiencing problems, it will have a direct impact on the ability to store and access data. In addition to storing and retrieving files, the server also bears the load of processing applications. Network bottlenecks and slowdowns in data availability may occur as server bandwidth is consumed by applications, especially if there is a lot of data being shared.

Direct attached storage is ideal for localized file sharing in environments with a single server or a few servers - for example, small businesses or departments and workgroups that do not need to share information over long distances or across an enterprise. Small companies traditionally utilize direct attached storage for file serving and e-mail, while larger enterprises may leverage direct attached storage in a mixed storage environment that likely includes NAS and SAN. Direct attached storage also offers ease of management and administration in this scenario, since it can be managed using the network operating system of the attached server. However, management complexity can escalate quickly with the addition of new servers, since storage for each server must be administered separately.

From an economical perspective, the initial investment in direct attached storage is cheaper. This is a great benefit for IT managers faced with shrinking budgets, who can quickly add storage capacity without the planning, expense, and greater complexity involved with networked storage. Direct attached storage can also serve as an interim solution for those planning to migrate to networked storage in the future.

Network Attached Storage
(NAS)

File Level Data Sharing Across the Enterprise

Networked storage was developed to address the challenges inherent in a server based infrastructure such as direct attached storage. Network attached storage, or NAS, is a special purpose device, comprised of both hard disks and management software, which is 100% dedicated to serving files over a network. Network attached storage relieves the server of storage and file serving responsibilities, and provides a lot more flexibility in data access by virtue of being independent.

NAS is an ideal choice for organizations looking for a simple and cost effective way to achieve fast data access for multiple clients at the file level. Implementers of network attached storage benefit from performance and productivity gains. First popularized as an entry-level or midrange solution, network attached storage still has its largest install base in the small to medium sized business sector. Yet the hallmarks of network attached storage which are simplicity and value are equally applicable for the enterprise market. Smaller companies find network attached storage to be a plug and play solution that is easy to install, deploy and manage, with or without IT staff at hand. Thanks to advances in disk drive technology, they also benefit from a lower cost of entry.

In recent years, network attached storage has developed more sophisticated functionality, leading to its growing adoption in enterprise departments and workgroups. It is not uncommon for network attached storage to go head to head with storage area networks in the purchasing decision, or become part of a NAS/SAN convergence scheme. High reliability features such as RAID and hot swappable drives and components are standard even in lower end network attached storage systems, while midrange offerings provide enterprise data protection features such as replication and mirroring for business continuance. Network attached storage also makes sense for enterprises looking to consolidate their direct attached storage resources for better utilization.

Since resources cannot be shared beyond a single server in DAS, systems may be using as little as half of their full capacity. With network attached storage, the utilization rate is high since storage is shared across multiple servers.

Storage Area Network
(SAN)

High Availability for Block-Level Data Transfer

Storage area network, or SAN, is a dedicated high performance storage network that transfers data between servers and storage devices. In contrast to DAS or NAS, which is optimized for data sharing at the file level, the strength of storage area networks lies in its ability to move large blocks of data. This is especially important for bandwidth intensive applications such as database, imaging and transaction processing.

The distributed architecture of a storage area network also enables it to offer higher levels of performance and availability than any other storage medium today. By dynamically balancing loads across the network, storage area networks provide fast data transfer while reducing I/O latency and server workload. The benefit is that large numbers of users can simultaneously access data without creating bottlenecks on the local area network and servers.

Storage area networks are the best way to ensure predictable performance and 24x7 data availability and reliability. The importance of this is obvious for companies that conduct business on the web and require high volume transaction processing.

Storage area networks have built in a wide variety of failover and fault tolerance features to ensure maximum uptime. They also offer excellent scalability for large enterprises that anticipate significant growth in information storage requirements and unlike direct attached storage, excess capacity in storage area networks can be pooled, resulting in a very high utilization of resources.

There has been much debate in recent times about choosing SAN or NAS in the purchasing decision, but the truth is that the two technologies can prove quite complementary.

Today, storage area networks are increasingly implemented in conjunction with network attached storage. With SAN/NAS convergence, companies can consolidate block level and file level data on the same storage solutions. Two such solutions that offer both NAS and SAN functionality are OPEN-E DSS and Windows Storage Server 2008.

Summary

With such a variety of information storage technologies available, what is the best way to determine which one is right for your organization? DAS, NAS and SAN all offer tremendous benefits, but each is best suited for a particular environment. Consider the nature of your data and applications. How critical and processing intensive are they? What are your minimum acceptable levels of performance and availability? Is your information sharing environment localized, or must data be distributed across the enterprise? IT professionals should make a comprehensive assessment of current requirements while also keeping long term business goals in mind.

Like all industries, storage networking is in a constant state of change. It's easy to fall into the trap of choosing the emerging or disruptive storage technology at the time. But the best chance for success comes with choosing a solution that is cost effective and provides long term investment protection for your business or organization. Make sure your storage infrastructure is conducive to cost effective expansion and scalability. It is also important to implement technologies that are based on open industry standards, which will minimize interoperability concerns as you expand your network.

DAS, NAS and SAN Server Solutions

Broadberry Data Systems offer a wide selection of cost effective, high performance direct attached storage, network attached storage and storage area network solutions. Please click here to view our complete DAS, NAS and SAN range. If you do not see a DAS, NAS or SAN storage solution that meets your requirements we can custom build and configure a configuration to meet almost any specification. Call us on 1-800-496-9918 where one of our experienced sales & technical staff can help you to determine the appropriate DAS, NAS or SAN configuration for your exact requirements.

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