Vendors Large And Small Flock To Thin Provisioning Storage

Given the continuing growth of the amount of data businesses must store and manage, it often appears that storage solution providers have to resort to magic tricks to make some of the required capacity disappear while keeping the data available.

One of those "tricks" is actually the greatest act of prestidigitation in the IT industry: thin provisioning, which gives applications the illusion that they have much more capacity than is actually available.

Thin provisioning is a type of storage virtualization which allows a storage administrator to allocate more capacity to specific applications or users than is physically available under the assumption that not all those applications and users will need the entire allocated space simultaneously. This allows extra physical capacity to be installed at a later date as the total amount of space actually used approaches the current installed capacity.

The availability of thin provisioning technology is expanding throughout the storage industry as vendors large and small make it available to partners and customers.

For instance, Hewlett-Packard last year acquired enterprise storage vendor 3PAR in part because of its industry-leading thin provisioning technology.

HP this year even added thin provisioning capability to its EVA storage array line, a line that has been in the market since 2001.

At the other end of the spectrum, Data Robotics, manufacturers of the Drobo-line of SOHO storage appliances, in February added automated thin provisioning to its SMB storage appliances, a move which the company's own executive called "unusual" for SMB storage.

In addition, thin provisioning has become an expected part of nearly every offering from startup storage vendors.

For instance, Pure Storage, a Mountain View, Calif.-based startup developer of storage arrays designed specifically as an all-Flash memory storage appliance, last month unveiled is first array, which included thin provisioning among its feature set.

Another startup implementing thin provisioning is SolidFire, a Boulder, Colo.-based developer of SSD storage technology combined with scale-out storage architecture used to increase performance when multiple users attempt to access cloud-based storage.

Thin provisioning has become a standard check-box feature for storage, said Greg Knieriemen, vice president of marketing at Chi, a Cleveland, Ohio-based solution provider.

"There's an expectation that the solution will include it," Knieriemen said.

However, Knieriemen is not so sure that thin provisioning will catch up on in SMBs. "Smaller environments don't really need it," he said. "It's like arguing why you need deduplication in a 4-TB box. Just buy another hard drive."

Thin provisioning is typically baked into the cost of the array, and usually there is no charge to turn it on, Knieriemen said. "It used to be a licensable feature, but not now," he said.

The difference between vendors in regards to thin provisioning lies in how good their capacity alerts are as the applications reach 75 percent to 80 percent of their provisioned capacity, Knieriemen said.

"When applications meet the thresholds, they need the appropriate alerts," he said. "Are the alerts e-mail-based? Phone home? A big red light on the box that flashes to say you better add more capacity now?"

Thin provisioning is a great way to talk to customers about their return on investment, or ROI, said Dave Butler, president of Enterprise Computing Solutions, a Mission Viejo, Calif.-based solution provider.

"The key is to move the dialogue beyond the feature to the ROI," Butler said. "If a customer says, 'I calculated I need 40 TBs,' you can say, 'No, you maybe need only 25 TBs.'"

Next: Taking Advantage of Thin Provisioning

Enterprise applications which use up the maximum amount of physical storage capacity allotted to them at best suffer from a decrease in performance or at worst crash completely. Therefore, IT administrators must ensure that they have enough unused capacity to meet expected future requirements.

However, when multiple applications are each allocated extra capacity, the result is a severe underutilization of a storage array's or a SAN's total capacity, forcing businesses to purchase more storage capacity than actually needed.

Thin provisioning, which is a feature of most major storage arrays, helps eliminate that underutilization by causing applications to think they have more capacity than needed without actually allocating that capacity until it is required. It relies on the ability of a storage array to automatically grab more physical capacity from a pool of unused disk space and re-assign it to an application as it is needed rather than assigning large amounts of physical capacity to the application.

The ability to better manage growing storage capacity is a critical need for businesses.

IDC, in its fifth annual survey on the state of the digital data universe, said in June that the amount of data being stored is more than doubling every two years, and could grow by 50 times by 2020.

In the survey, IDC found that the amount of data created and replicated is expected to top 1.8 zettabytes, or 1.8 billion TBs, in 2011, up from just over 1 zettabyte in 2010.

IDC also reported that 75 percent of the information being created today is coming from individuals who write text, take photos, or upload videos and music, and that information about such individuals is actually growing faster than data created by them. However, IDC said, enterprises will at some point be responsible for some part of the liability of 80 percent of that data.

Thin provisioning has a couple of advantages compared to traditional storage provisioning.

The primary advantage is a lower cost for storage. With traditional provisioning, an IT manager would have to purchase and deploy excess capacity for multiple applications separately. With thin provisioning, all the excess capacity sits in a single pool that is available to those multiple applications as needed regardless of how much capacity each application thinks it can access. However, since the various applications will require additional capacity at uneven rates, the total amount of physical capacity needed will be less than the total sum of the individual physical capacity of each application under traditional provisioning.

In addition to the lower capacity requirements needed under thin provisioning, another advantage lies in the fact that the per-GB cost of storage typically falls over time. As a result, purchasing smaller amounts of capacity in several stages while prices drop cuts the cost of storage compared to purchasing it in larger lump sums.

The other advantage of thin provisioning is increased management flexibility. With thin provisioning, IT administrators will be required to physically add capacity based on the overall storage requirements, whereas with traditional provisioning there may be more work involved in maintaining the capacity requirements of multiple applications.

Thin provisioning technology typically sends alerts when the capacity used reaches a certain threshold, such as 90 percent of provisioned capacity, giving administrators the opportunity to allocate more disk space to the application.