If processing power doubles every 18 months as per Moore’s law, what about the other aspects of computing? For instance, is there a law for storage—the most critical part in enterprise computing? If yes, we havent heard of it. And that’s why storage is the most talked about and least understood frontier among enterprises. Most learn the hard way, only a crisis bringing to fore the absence of a robust and comprehensive storage infrastructure. However, after 9.11, many companies have realized the criticality of data and are hence putting in place some or the other form of storage architecture. With more emphasis on infrastructure augmentation, Year 2002 can be called "introspective" for many organizations. As a result, IT spend in segments like storage remained stable throughout the year. According to industry estimates, around 35% of any enterprise’s IT budget will go toward storage-related expenses in 2003.

WHO’S THIS STORY FOR? An IT chief facing growing stacks of data, and struggling to make it available and reliable WHAT DOES IT COVER? n How do I work out storage needs for business apps? n Do we need to upgrade our storage? n Which storage solution..? n How do I consolidate our storage n We're not that big:should I look at NAS and SAN?

Data has become mission critical—in some cases, a lifesaver. To protect data, CIOs to-day have to evolve a comprehensive storage management policy. And this policy that they come up with has to be in sync with the organization’s business goals. A Frost&Sullivan study suggests that a good storage management policy begins with the definition of storage limits or quotas for the users, so that everyone across the organization gets proper storage facilities.

This brings in one very critical question—How does one effectively manage storage? Before searching for answers, lets look at the current state of storage in most Indian enterprises. Two scenarios emerge here—One is a total lack of storage awareness... the other, the inability to utilize whatever storage facilities are available. In order to devise storage architecture, an enterprise needs to assess two factors that will clearly bring forth the state of storage bandwidth it has, and will set stage for the next level of maturity. Also, many organizations fail to utilize the existing storage due to a combination of reasons and as a result most of them end up using only 60% of the storage space. This is mainly because most storage space is often attached to servers and, hence, spare capacities in multiple servers becomes redundant.

Managing storage: Beyond DAS
Once the initial data mapping is done, the crucial part is in identifying the right kind of storage. Storage buying should be driven by the organization’s business goals rather than by popular perception. Here enterprises have multiple options before them and the three major topologies—DAS, NAS, and SAN are still the most preferred form of storage. However Direct Attached Storage (DAS), the most common form is slowly loosing its relevance and Network Attached Storage (NAS) and Storage Area Networks (SAN) are gaining ground. DAS might hold well for SMEs, but when the storage level exceeds the million-megabyte mark, then it is time to migrate to a NAS architecture that solves many problems associated with DAS.

The advantage of NAS is TCO and ease of use. For instance it can be configured to the existing client set up in minutes due to its plug and play nature. Any organization aiming for effective server management and file sharing should go for NAS.

However, since NAS runs on corporate LAN, network congestion happens and might lead to downtime, but effective network management and bandwidth allocation will often fix the problem.

NAS-SAN convergence
Traditionally, in a SAN setup, data gets transferred over a storage loop to the various devices connected with the SAN. The storage media for SAN is based on the SCSI disks, tape drives, and off late fiber channel interface drives are being used.

SAN is the most preferred set up that liberates the organization from storage hassles by providing a highly scalable architecture. Since SAN is based on a dedicated network, it liberates the LAN and replaces SCSI based interconnected storage devices with a fiber channel that brings in data transfer speeds to the tune of 100MB per second and a typical SAN can support up to 128 devices and with switching technologies this can be scaled to thousands of storage devices.

However such raw power does come with some issues. Managing a SAN is not easy, particular when an organization has multiple server platforms. But interoperability issues will no longer hamper SAN adoption because the Storage Networking Industry Association, in association with 11 major storage vendors, has created specifications that should be followed in a SAN implementation. The specifications will enable administrators to use a common set of storage management tools to manage software and hardware from different vendors.

A recent development in the storage industry is the convergence of NAS and SAN. Today, NAS is seen as a prelude to SAN implementation. Moreover experts suggest that the trend will move towards making NAS as the front end and SAN as the backend of the storage infrastructure. The key driver that is propelling this convergence is the advantage of NAS in the file-sharing environment, whereas in a SAN it is not possible. Hence, adding NAS as one of the functionalities of the SAN makes better sense. The question is—how can competing architectures converge? They can. For instance, there’s a clear difference between shared storage and shared files. While SAN shares the storage resources through a common network, NAS shares files through an IP network. By uniting the two concepts, files can be accessed through NAS and delivered by SAN. When these two converge, we have a fourth topology—consolidation or shared storage.

Shared storage
In simple terms, shared storage is nothing but sharing of contents between multiple client entities by putting in place a combination of technologies at work—like NAS, SAN, tape, virtualization etc. The idea behind a shared storage is to consolidate the gamut of data that runs through the enterprise. For instance in a robust data-sharing environment, users will be able to share data irrespective of the platform on which it runs. For example a Windows application can be shared with a user running UNIX. This seamless integration is the major advantage of shared storage. Lets sample another scenario—when an enterprise with a typical DAS architecture has a large number of RAIDS (Redundant Array of Independent Disks), by consolidation, the number of RAID systems can be narrowed down to two or three units. The return on this kind of RAID revamp will be the drastic increase in the per user storage allocation which is between ten to 15 times after consolidation.

Virtualization
Consolidation of storage into a centralized storage repository happens through virtualization. In a shared environment, storage solutions from multiple vendors and platforms are involved. A typical virtualization will group all these multiple storage areas into one single entity. Virtualization sets the stage for effective data management as it separates space hungry data intensive apps and low bandwidth applications. This separation makes it possible to run mission critical applications with relative ease.

According to Aberdeen Group, virtualization eliminates server downtime by about 30%, since it can be re-configured dynamically.

Storage resource management
Virtualization cannot happen on its own, and the key driver here is storage resource management (SRM) software. This enables virtualization by taking the inventory of the physical assets (the number of storage devices) and digital assets (the volume of data that resides in the devices) and prescribes various parameters and allocation to the storage administrators in effectively managing the storage resources. Also with the advent of storage controllers, shared storage and virtualization has become easier.

As IT usage and automation increases, enterprises are prioritizing storage. This is because the organization’s entire digital assets reside in the storage infrastructure. If data has to be accessed from anywhere and at anytime, the storage architecture a CIO is putting in place makes all the difference. As an Aberdeen research aptly sums up, " A storage infrastructure has to fundamentally do three things—store data, move data where needed and make the previous two manageable. Probably the biggest challenge a CIO has to deal with is managing these three effectively and arriving at a storage management infrastructure!

Shrikanth G