As storage networks continue to grow in size and value, companies are finding that storage virtualization tools enable them to better manage their storage resources and optimize their data.
Simply put, storage virtualization is the ability to arrange multiple physical storage devices, such as disk or tape arrays, into single, logical, "virtual" entities that appear as one disk to the network operator. This single virtual storage disk then becomes easier to manage, improving the performance of the storage network and allowing for rapid storage growth and reconfiguration without unnecessary downtime, a requirement that has become vital to e-business.
Hardly a new idea, the idea of storage virtualization is a throwback to the days of the mainframe environment, according to Veritas Software Corp., makers of Veritas Volume Manager, a storage virtualization tool targeted at maximizing SAN (storage area network)-based application uptime for Internet businesses.
Virtualization continues to have a place in modern e-business networks, supported by technology from Hopkinton, Mass.-based EMC Corp. and XIOtech Corp., to name a few.
"When you have true virtualization, every server gets the power of every actuator on every single storage disk simultaneously. It's similar to having a bunch of cars in a parking lot and allowing whoever is driving one of them to have all the power of all the engines that are sitting in the lot," explained Philip Soran, founder, president, and CEO of XIOtech, based in Eden Prairie, Minn.
Much like a parking lot of cars, modern enterprise storage networks are commonly made up of a number of different storage devices, which, if left to operate on their own, can create a nightmare for network administrators trying to balance all the individual resources and remember the configurations and limitations of each storage device.
When coupled with the company's Magnitude SAN server, XIOtech's Redi virtualization software can intelligently map data from all the different storage devices and combine them into one or more virtual storage disks. The free space on any partially used drives will be utilized with any new storage the user adds to the network, distributing new data across the SAN rather than directing it to a specific device.
Kee Kimbrall, the president and CTO of 10K Wizard, a Dallas-based provider of online access to real-time Securities and Exchange Commission filings, says he designed the company's storage network to utilize virtualization.
Kimbrall's 10K Wizard storage network, which at any given moment cross-references over 8 billion records, running data searches and generating alerts, uses virtualization in place of partitioning between mixed storage devices.
"Now if I have a 100GB disk and I need to expand to 200GB, I can go and type the command in and it's done," Kimbrall says. "I knew virtualization was the solution, so I didn't partition because the virtualization is one big partition."
Kimbrall says that because disks read and write data sequentially, it's faster to write portions of a large file across many disks that are working in parallel than to write onto one stand-alone or partitioned disk.
The ability to write data across all storage drives and utilize all available space in a SAN enables companies to redistribute storage capacity without concern for the individual characteristics of the separate storage drives.
This type of virtualization also aids servers attached to the storage network in accessing data faster, as all the disk actuators in the storage network are available to execute application read/write requests and searches.
"If someone needs to run a large application, we can allocate more space," explains Rob Kinney, a network developer and engineer at Ohio State University's Fisher College of Business, which uses virtualization to manage its storage. "Then when the project is over, we can take [the once-allocated storage] back without going offline."
Allocating storage instead of buying additional storage for certain applications can also save companies money, another key benefit to storage virtualization.
EMC's family of Enterprise Storage Network (ESN) components offers a variety of virtualization options, and the Veritas Volume Manager from Mountain View, Calif.-based Veritas Software also allows for storage virtualization.
Nearly all available virtualization software can be integrated into existing operational networks.
"We have old Windows NT and Linux servers that are hooked to the XIOtech [virtualization software], and it does not care - as long as there is a driver, you can hook up Sun boxes, NT, Linux, you name it," said Kimbrall.