Virtualization drives storage management advances

Going thin

Some storage vendors have adopted the concept of thin provisioning to solve customers' need for dynamically allocated storage.

With thin provisioning, a single pool of storage that can handle the growth requirements of applications is set aside. Allocation of storage capacity to applications can reach more than 100 percent, but because no application will at any one time consume all the storage available, capacity is left in the pool.

The use of thin provisioning eliminates over-provisioning of storage, in which storage capacity is pre-allocated to applications but never used. Among the companies using thin provisioning in their products are 3Par, Network Appliance, Compellent, LeftHand Networks, DataCore and Equallogic.

Gary Berger, vice president of technology solutions for Bank of America Securities Prime Brokerage in New York City, uses 3Par's thin provisioning to allocate storage for his IBM BladeCenter server environment.

"In early 2005, we had a very fragmented environment [with lots of silos] everywhere," Berger says. "We spent most of our time catching up and sending disks around the country to recreate disk allocations and whole allocations, which provided the difference between what was useable and what was allocated. Virtualization helps us distribute workloads across many different physical resources."

Berger has two mirrored data centers with a consolidated SAN infrastructure. He is using 3Par's "chunklet" technology, which breaks disk allocation into 256MB groups to distribute workloads across many different disks in his system.

"When we need to do capacity upgrades, we can simply add new disk magazines to the system and rebalance our allocation across those disks again to get more efficiencies," Berger says.

Berger also uses the 3Par software and hardware to boot his servers from the SAN.

"Being able to export a [group of disk volumes] to a blade server gives us a tremendous amount of capability because we can easily recover from simple hardware failures," he says.

Spotting deficiencies

In a perfect world, the process of identifying application-related compute or storage deficiencies and allocating more resources would be automated. Decreases in the performance of an application automatically would spawn the allocation of more compute or storage capacity.

A few vendors -- including start-ups Akorri and Onaro -- have introduced software that correlates dependencies among servers, storage and applications, and monitors and analyzes those dependencies. But these tools are predictive in nature and enable the manual change of server and storage resources, not the automated handling many users desire.

Meanwhile, software such as HP's Storage Essentials and IBM's Virtual Manager and System Director are starting to provide links between storage and server connectivity.

Another option for automating storage provisioning is HP's Virtual Connect, which pools and abstracts LAN and SAN connections to servers and virtual machines in HP BladeSystems. It lets administrators define a server's I/O connections and then migrate data to another server or virtual machine without disturbing the LAN or SAN settings.

For its part, Veritas offers Server Foundation and its components, Provisioning Manager and Application Director, which automate the provisioning and management of virtual servers and storage.

As tools such as these mature, the convergence of server and storage virtualization will move closer to reality.