Storage Special: NAS & SAN

NAS and SAN: perfect partners

Some say that NAS competes with SAN and that the two will eat into each other’s market. But Gaurav Patra says this is no longer a valid theory since industry pundits now swear by the convergence of the two

NAS as the front-end and SAN as the back-end of the storage infrastructure will soon become a reality, says B Chandrasekhar

The explosive growth of data is driving organisations to adopt a cost-effective approach to data storage. Many organisations have decided to look ahead and avoid investing in technologies that are sooner or later going to become obsolete. Probably because of this, enterprises large and small have started shifting their focus away from Direct Attached Storage (DAS), a technology that many believe will not keep up with the demand for storage. This has paved the way for newer technologies like Network Attached Storage (NAS) and Storage Area Network (SAN).

Organisations have realised that their corporate data is more important than their servers. This has led them to migrate to SAN and NAS architectures to ensure a higher level of data protection and advanced functionality. Gartner estimates that SAN will account for 49 percent and NAS for 32 percent of storage revenue in India by 2005. According to industry sources, SAN and NAS are now growing at roughly 80 percent year-on-year.

Similarly, IDC expects a sequential growth of 50 percent in 2003 over 2002 for external storage in India. It says that DAS will account for a major chunk of that, but NAS and SAN are expected to grow faster in the coming years because of data explosion and the limitations of DAS in terms of data manageability. An interesting development is that even in smaller cities, companies are now adopting SAN and NAS. "According to IDC, the growth in both SAN and NAS segments has been around 50 percent. In the days to come, NAS will grow more in terms of volumes and SAN will grow more in terms of value," says Avijit Basu, marketing manager, NSSO, HP India. Adds P K Gupta, director, Intercontinental Operations, Legato, "The NAS market saw a surge in demand last year and is growing faster than the SAN market."

P P Subramanian, country manager, India, Hitachi Data Systems, agrees that there’s an upswing. He says that a couple of years back there were only around 4-5 SAN implementations, but today there are around 40 installations of SAN in India.

With the increase in demand for data storage, not only has the interest in networked storage increased tremendously, but actual purchasing patterns have also changed. Today, companies are increasingly considering SAN components as part of their overall architecture from the very beginning.

In the small and medium enterprise (SME) segment, the focus is more on reliability and affordability. Industry sources believe that NAS-based storage has penetrated the SME segment both because of ease of use and the lower cost of hardware and maintenance. Some SMEs are going in for popular Fibre Channel-based solutions with small SANs in place. The back-up systems chosen by these customers are also much smaller than those chosen by enterprise customers. In industries like software development, a combination of SAN and NAS technologies is gaining ground. While software developers prefer to deploy SAN, the ability to allow network users to directly access the disk for specific project purposes is a very popular architectural demand.

However, in case of file server environments, Web hosting, CAD/CAM, etc, where considerable file-sharing take place, NAS is predominant because of its support to this activity. In case of enterprise-wide storage consolidation and business continuity management planning, SAN is an effective solution that’s emerging.

The fusion of NAS and SAN is an emerging trend. In this, the back-end, which is an array of disks, remains the same, and it can be used by both the technologies. The front-end can be NAS or SAN, says Avijit Basu

Getting together

One of the most important developments is the convergence of NAS and SAN. "NAS will be seen as a prelude to SAN implementation. Further, NAS as the front-end and SAN as the back-end of the storage infrastructure will soon become a reality," opines B Chandrasekhar, manager, storage, Sun Microsystems India. While SAN shares storage resources through a common network, NAS shares files through an IP network. By uniting the two, files can be accessed through NAS and delivered through SAN thus providing a new topology—consolidation or shared storage.

Says Basu, "The fusion of NAS and SAN is an emerging trend. In this, the back-end, which is an array of disks, remains the same, and it can be used by both the technologies. The front-end can be NAS or SAN. Hence there is no need to replicate the disk array twice as the array can be common for both NAS and SAN." This means cost savings and also easier management.

The market for converged NAS and SAN will grow as the technology matures. "SAN and NAS complement each other. NAS provides high-speed file services to networked clients while SAN provides high-speed storage services to servers at the block-level on a neutral server platform," says Gupta.

The convergence of SAN and NAS will lead to better storage solutions for enterprise customers. The fusion will remove misconceptions about these technologies from users’ minds. Together they cater to possibly all kinds of performance requirements an enterprise may have.

Verticals that matter

As far as adoption is concerned there is no demarcation for any specific technology to be adopted by any specific sector, but primarily banking, financial services and insurance (BFSI), telecom, manufacturing and a few IT companies and government organisations have implemented SAN in their networks. Being an excellent solution for file-sharing, NAS is very popular among software development firms. It is also relatively cheaper to implement since it can use the existing IP network.

Medium-sized enterprises are also adopting SAN. Considering the rate at which data is growing, even medium-sized enterprises now need solutions to store multiple terabytes of data. They cannot use DAS. This is the same situation that large companies were facing earlier.

The NAS market saw a surge in demand last year and is growing faster than SAN, says P K Gupta

Growth drivers

Consolidation of storage resources is one of the primary reasons why enterprises are moving towards SAN-based solutions. Consolidation provides easy management of storage resources, and allows companies to plan their budget accordingly, instead of buying a lot of storage space on day one.

In addition, costs of both SAN and NAS are going down. "Whether it is SAN or NAS, the cost of disk drives is declining, and this is good news," says Anal Jain, president, India & SAARC, Network Appliance. Apart from this, the price of the electronic hardware/computer system on SAN and NAS, the cost of the channel connection, and the cost of IP adaptors have been further reduced, which will also boost demand. "Costs of NAS and SAN have come down by almost 30-40 percent. However, the rate at which people are adding data is higher than this, so it compensates," says Jain. Declares Basu, "Growing awareness and falling prices are the primary drivers. Indeed, prices will continue to fall. There will be more storage available at a lesser price."

Other factors that are driving SAN and NAS are the benefits of adoption, the growing amounts of data, and the increasing complexity of managing data. In future there will be more business-critical applications which will directly fuel the growth of NAS and SAN.

Another factor that will provide support is storage virtualisation. HP’s ‘adaptive storage infrastructure’ is a case in point; the company is promoting the maximum utilisation of networked storage through virtualisation.

The emergence of departmental SANs is another trend to watch. Earlier, this was popular only in the enterprise environment because of the cost factor, but with the price decline this concept is getting more popular in smaller organisations too.

Areas of concern

The need to take control of the company’s data storage assets has led to centralisation of storage assets. This centralisation has many advantages in terms of day-to-day management. Since it also lowers the overall cost of storage systems ownership, the set-up is converging towards an intelligent infrastructure for data storage. This approach requires new layers of control and intelligence to be built into the storage network. New IP-oriented block protocols such as iSCSI and FCIP are nearing ratification as standards. They provide new methods to extend reach, to increase applicability, to lower overall cost, and to improve manageability and security of networked storage. "However, first-generation SAN products do not yet support these emerging protocols. Thus, when expanding or redesigning the storage network, users today have to make sure that
they can easily upgrade to these new capabilities," says Chandrasekhar. Another concern is cost. The price of implementing a SAN solution is still not low enough to drive mass adoption.

"Investments in SAN will go up from 19 percent in 2001 to 35 percent in 2003. In the case of NAS, it will climb from 6 percent to 21 percent, while DAS will go down from 75 percent to 44 percent," says Gupta. As these technologies mature and new standards emerge, one expects to see storage being managed as a separate and distinct entity.