A CIO had been struggling to keep up with the increasing demand for data storage capacity. He wanted to expand the storage capacity by cutting down the painstaking migration and integration processes. Having installed virtualization software on a SAN, however, he can pool all his data regardless of which device it comes from and manage it on a single web console. Besides, a few of his NT servers were utilizing only half of their disk space. All these issues were sorted out using the virtualization software solution. Now, the CIO can cut costs by reducing the number of disks and can buy devices of different kinds. He need not bring down the network whenever he needs to re-configure the SAN.

Storage virtualization promises to enable users to pool together data from any type of physical device. Here, the pooling can be done irrespective of the vendor or device type. However, vendors have been providing their own definition of the term, depending on whether they are offering virtualization at the storage device, network device or server level. But what remains to be seen is whether virtualization solutions offered by vendors are fulfilling the promise of unifying devices.

"Each sector of the market has its own strategy to take advantage of the opportunity posed by storage virtualization. This automatically leads to some difference in answers. However, by and large all of them basically denote the same thing. Though the tracks are different, the direction is same," says Owais Khan, business manager, enterprise solutions, Compaq.

"Organizations around the world and in India are facing an exponential growth of information. The key challenge is to manage the information explosion with a limited budget and resources i.e. do more with less. So virtualization is all about automation and simplicity," says T Srinivasan, country manager, EMC.

The concept of virtualization is typically treated as an extension of a SAN environment and users cannot utilize the full potential of SAN (and NAS) without virtualization. Therefore virtualization is to be looked upon as adding more to the existing features of SAN and in most cases, NAS.

"More and more people will understand the benefits of virtualization and use it. Virtualization and physical networks with DAS, NAS and SAN will co-exist," says Avijit Basu, marketing manager (NSSO), HP.

Where will it exist?
Storage virtualization can happen at the server, the network device (fabric switches/router) and at the storage device levels. There is an ongoing debate about the level at which virtualization would be most effective (sometimes even a combination of all these levels are used to bring about the most from virtualization).

Storage Virtualization Gives You: The ability to logically consolidate or pool storage from various vendor sources and/or various storage systems on a SAN  Control over how that logical storage is configured and used   Utility software services such as remote mirroring and point-in-time snapshot copying to facilitate ensuring business continuance and   Dynamic storage reconfiguration without interrupting applications running on host servers connected to the storage  Source: Aberdeen Group

Software companies like Computer Associates (CA), Veritas, and Tricord offer server based virtualization software solutions. These software tools provide a single point of integration and control storage devices by pooling data from across devices and networks. For example, CA’s solutions along with SAN and NAS management capabilities manage storage appliances. "Lately, there has been a trend to evaluate purely software based virtualization (server level) solutions that make virtualization independent to the architecture (SAN/NAS) as well as the storage fabric (fiber channel or gigabit Ethernet)," says Rohit Ghai, CTO, CA.

Software almost always accompanies virtualization. The infrastructure for virtualization would be either purely software based, software with a firmware (on the storage device) or software along with a virtual storage device," says Ghai. According to Basu, "In most cases, the customer need not buy any infrastructure apart from our storage virtualization device. The idea is to have zero impact on the host and other than data migration, there’s no change. The cost depends on customer requirements."

The right time is now
SANs are expected to exploit virtualization in a major way. "SANs are being deployed in increasing numbers and it is the next logical step to embrace a virtualization solution with a SAN. By the end of 2002, half the major IT-utilizing enterprises will have some type of SAN installed and a high percentage of those will have a virtualization solution," says Khan.

Organizations, when investing in storage, should consider virtualization as well. "As organizations begin to realize and assess their storage needs and requirements, they need to invest in storage virtualization appropriately. However, investing in storage virtualization depends on any company’s storage requirements," says M Ganesh, enterprise systems group, IBM.

Those intending to use the technology must first fully understand what virtualization has to offer. They must know what to ask for and not fall for the claims made by vendors. They must ignore the features that vendors promise but stress on the benefits that they would accrue on implementation. " Businesses must bear in mind that virtualization is only a piece of the overall storage management solution. Many virtualization solutions available offer nothing more than just disk pooling and lack in full functionality," cautions Srinivasan.

Is SAN the only option?
With a vast majority of storage still on DAS and NAS environments, will virtualization extend beyond SAN? "Storage virtualization for DAS is possible but the rewards to be reaped do not justify the effort involved. As for NAS architectures, virtualization is definitely possible and has been implemented by certain vendors," says Ghai. He adds, "Virtualization in the NAS environment is definitely a more palatable option for SMEs from both a cost and manageability perspective."

Experts believe virtualization will make headway in India and APAC in the next two years. Khan adds that at a later stage, storage virtualization will be an all-pervading technology… very similar to ‘our daily bread and bandwidth’. Something which is a necessity, but not sufficient.

Radhika Bhuyan in New Delhi