Storage Special: Virtualization

Virtualisation: Integrating disparate islands of storage

If you wish to have a solution or technology to integrate your disparate storage devices and manage them as one logical unit, it may be storage virtualisation technology that you are looking for, say Stanley Glancy and Srikanth R P

Business is about data that requires analysis and speed. Data must be delivered in milliseconds as high-speed data-mining applications are continually sifting through mountains of information, says K P Unnikrishnan

Gopal Jain is the CIO of a large organisation that has just completed two acquisitions in quest for growth that defies the rate at which the industry is growing. But while everyone—right from the top management to the stock analysts are impressed with the inorganic growth route, Jain is still worried and perplexed. Perplexed, because as the CIO of the company, he has to not only integrate two diverse IT systems but make sure that there are no hitches in exchanging data between the diverse systems that are not interoperable.

Jain’s case is not unique and many Indian companies today face the same problem while integrating diverse storage systems from different vendors. Each player offers his own proprietary products and solutions. And more often than not, these products are not interoperable. The end result is a dissatisfied customer. Not only are his options restricted to a few players but he also doesn’t have much choice in the products available.

This is where storage virtualisation comes into the picture. Virtualisation provides the ability to view and manage multiple, networked heterogeneous storage devices as if they were a single pool of storage managed from a central console. To an operating system, the virtual storage appears as one device, regardless of the types of storage devices pooled. This also means that for the end enterprise-user, there is greater ease of attaching or detaching extra storage.

Virtualisation

Towards the end of the last millennium we have seen an increasing interest in things concerning the virtual. Virtual reality gaming centres mushroomed across the globe, changing the very idea about entertainment. These centres provide us with an experience of the actual without really being so. For instance, the virtual reality ride at theme parks tricks riders into believing they are flying over the city, by providing sensory clues to passengers, while keeping the mechanics of the ride hidden.

But what does the term virtualisation mean in the storage industry?

"Virtualisation is a vague term, and is probably one of the hardest words to understand and grasp today because it is descriptive of a technology, not a solution," says T Srinivasan, country manager for EMC. Similar to the virtual reality ride, a good virtualisation tool sets up a matrix in which the data (supposedly) is travelling on a familiar path, while enabling the operator to change the ride at will.

The best definition of virtualisation is probably data abstraction. The technology involves taking multiple physical storage devices and combining them into logical storage devices or units that are presented to the operating system, applications, and users. It builds a layer of abstraction above the physical storage so as not to tie data to specific hardware devices, providing a flexible storage environment.

Elaborates Deb Dutta, regional sales director–South Asia Pacific, Brocade Communications Systems, "In the storage industry, the term virtualisation describes the ability to view and manage multiple, networked, heterogeneous storage devices as if they were a single pool of storage." This is also the reason why the technology has been gaining rapid acceptance among enterprises.

Says Avijit Basu, marketing manager-NSSO, HP India, "Virtualisation unifies the myriad storage systems of an enterprise into a common resource, which can be provisioned, managed and supported in a consistent, coherent way." Technology can be incorporated into servers, storage, switches or other platforms to deliver value to customers through data services across heterogeneous systems, simplified management, higher uptime and flexibility in resource utilisation.

The Advantages of Storage Virtualization

Click on image for larger view

Advantages

Virtualisation of data resources separates fixed dependency between applications, operating environment and hardware. Even in a mixed rendered environment these resources can be allocated and reallocated on demand. Because resources are treated as a single system, the problem of managing individual components is done away with.

"Business is about data that requires analysis and speed. Data must be delivered in milliseconds because it is not just people who are asking for it, but high-speed data-mining applications continually sifting through mountains of information," says K P Unnikrishnan, country head-marketing, Sun Microsystems India.

Sun is aggressively pushing N1—the company’s vision for making entire data centres appear as one system. For example, today each application in a data centre has its own server, storage, and networking resources assigned to it. Because services and applications aren’t designed to share, each has to carry its own excess capacity in order to meet peaks in demand. By opening up previously static relationships between hardware, applications, and the operating environment, Sun is looking at positioning N1 as one solution to enable an organisation to easily deploy new services and dynamically allocate resources as business needs change. This means that excess capacity can now be managed and shared by a number of services in the same pool.

Storage virtualisation also helps reduce total cost of ownership (TCO). Though the cost of computing power and storage has been coming down steadily, managing data, and factors like security, data management etc are still too complex and costly. Storage virtualisation can potentially reduce costs through better hardware utilisation and consolidation. An application can use, request and change available storage based solely on its required attributes, without regard for location, physical organisation, or media type.

Today’s networks are optimised on a per application basis where each application gets its own dedicated mix of hardware, software, networking and storage. These static islands of data and software are difficult to manage efficiently. Because applications are not designed to share, the network is not fully utilised to its capacity. With N1, Sun is looking at scaling server utilisation rates from industry norms of 15 to 30 percent up to 80 percent or higher.

Virtualised storage is not restricted by the capacity, speed or reliability limitations of the physical devices that comprise them. This gives customers the ability to choose storage hardware independent of the functionality they need from it, and to change it and upgrade hardware without disrupting existing data—this independence from any single hardware vendor is key to operating with cost-efficiency. Additionally, with storage virtualisation, platform-independent, software-based solutions eliminate the cost and price premiums of exclusive solutions. It brings the entire storage infrastructure to the highest level at the lowest cost because the solutions work on a variety of platforms, with a wide range of storage hardware. Users can opt from among the various hardware vendors as needed and cross-train staff to use a single set of tools across the IT environment. The cost savings over time are significant, and solutions are consistent from platform to platform.

Virtualisation also allows companies to choose storage devices that best meet their needs, and then carve up these physical devices into logical volumes to provide resources as required. Combining storage virtualisation with storage resource management allows IT staff to visualise and monitor all the resources on the network, plan for capacity growth, and allocate resources according to business priorities.

Says Agendra Kumar country manager-India, Veritas, "Once an organisation is armed with cross platform virtualisation, organisations can create consistent business methodologies for managing application storage, regardless of platform. For example, companies using virtualisation for database storage can define corporate-level policies for the logical volumes and file systems that contain database and components, mandating certain levels of redundancy and performance." At the same time, separation of the logical and the physical layers provides the flexibility to change or reconfigure storage hardware transparently, perhaps swapping in higher-performing devices or moving storage to the systems that most need it, without interrupting access to data.

Ideally, technology should work in a completely heterogeneous environment, which includes multiple vendors and platforms for servers, software, network elements and storage devices. Storage virtualisation can ease the management of server and storage resources, whatever the architecture (DAS, NAS, and SAN) chosen by the customer. Storage virtualisation, even in a direct attached, open systems environment, helps IT organisations achieve the service level agreements (SLAs) they commit to, while simplifying system management and supporting and growing heterogeneous systems.

Perhaps the most useful outcome of storage virtualisation, according to Srinivasan, is that both users and vendors have a clearer understanding of the real challenge—open storage management (OSM). Enterprises want to control and manage all their storage arrays, regardless of vendor. They want to take the complexity out of managing large storage networks and automate and simplify tasks such as performance monitoring, allocation, utilisation, and backup, while leveraging their existing investments.

According to Deb Dutta, the objective of virtualisation is to allow any server to connect to a network and be unaware of the actual storage sub-systems connected to that network

Handling your legacy

Most businesses are generally not interested in the physical aspects of the storage serving their applications, such as seek time or rotational latency. Nor do they care how many disks are in a string or the mean time between failures for those disks. But users are concerned about issues like application response time and throughput, scalability as data generation grows, and application downtime.

The virtualisation layer offers a chance to combine physical devices into virtual entities that meet application requirements. For instance, a device that optimises performance for a specific application, while shielding users and applications from the physical details of the implementation.

Says Dutta of Brocade, "The biggest drawback in legacy-based systems is the difficulty in creating heterogeneous environments of servers that can share data. Storage virtualisation can overcome this problem as well as address a number of other network management issues. The objective is to allow any server to connect to a network and be unaware of the actual storage sub-systems connected to that network. Each server should see one large repository of data available as though it were direct-attached."

P K Gupta, director of Strategic Development, International Operations at Legato suggests a new approach for enterprises with legacy systems. He says, "There is a new approach coming in virtualisation through dedicated optimised storage appliance solutions. In this approach, storage virtualisation and management can be introduced in an incremental and non-disruptive manner, co-existing with legacy storage systems, DAS and SANs, protecting storage investments with the ability to migrate them to an IP SAN environment." This is one of the reasons why storage virtualisation as a concept is attractive to the end user.

Key drivers

Sectors that will drive growth in India for this concept are traditional sectors like banking, finance, insurance, telecom and manufacturing. Arun Rao, national manager of the Storage Business at CA believes that of all the sectors, the financial and telecom sectors stand to benefit the most from adoption of storage virtualisation technology. Vendors are also optimistic about the fact that various market reports are predicting that close to 50 percent of overall IT expenditure will be directed towards storage management solutions by 2004. Additionally, recent trends have shown that storage management tools are being adopted by even small organisations.

Says Rao of CA, "Most virtualisation initiatives have manifested themselves in a SAN environment in the Asia-Pacific region But each organisation, as it procures storage widgets, should have virtualisation at the back of its mind." Lately, there has also been a trend to evaluate purely software-based virtualisation solutions that make virtualisation independent of the architecture (SAN vs NAS) as well as the storage fabric (Fibre Channel or Gigabit Ethernet). Virtualisation for DAS is also possible but most analysts believe that the rewards to be reaped do not justify the effort involved. As for NAS architectures, virtualisation is definitely possible and has been implemented by certain vendors. For SMEs the same benefits apply, although the scale is smaller. Virtualisation in the NAS environment is definitely a more palatable option for SMEs from both a cost and manageability perspective.

While there are many products in the market today that are delivering virtualisation capabilities, an organisation should select only those products that provide an analysis of return on investment (RoI) and total cost of ownership (TCO). Organisations should also realise that while virtualisation is an important element, it is only a piece of the overall storage management solution.