When storage-virtualization technologies started their migration from the high-end mainframe marketplace to the low-end PC arena--back around the turn of the century--analysts were careful to point out that early virtualization successes in the PC market weren't indicative of long-term success prospects for low-end virtualization technologies. Fast-forward to 2006, and you'll find that certain aspects of storage-virtualization technologies have gone from rare and difficult to administer to commonplace and straightforward to manage.

Storage virtualization presented itself to the market as a panacea for the significant costs associated with storage hardware. Mainframe-class virtualization solutions let administrators provide pooled storage to clients, giving them access to all the virtual storage space they could possibly require. These solutions also let administrators play tricks with virtualization that minimized the actual amount of physical storage they needed to purchase. But a funny thing happened on the way to fully implemented virtualization: The cost of physical storage began to drop significantly as the performance and capacities of low-cost hard drives improved, making them an attractive choice for many storage solutions, including enterprise-class ones.

This market change hasn't had a negative impact on storage virtualization, though. In fact, it has made virtualization-related technologies even more relevant and applicable across a much broader potential market than early vendors had expected. The techniques and technologies developed to fruition by virtualization providers, such as automated replication, disk snapshots, and most importantly, the ability to manage multiple data versions and large amounts of data and physical storage, have led to real-time replication, continuous data protection (CDP), and other software/hardware combination products, all of which require huge amounts of storage.

The flip side of the cheap storage equation is the explosive growth in the amount of data that's kept online and the expense of backing up and managing that data. As online backup develops into a standard backup technology, the issues involved in backing up primary data become simpler, but the additional live storage makes managing storage exponentially more complex. Because the backup is hard-disk-based and online, storage administrators who formerly just needed to make sure that the live data was kept available now are responsible for the live data, multiple replicas of that data, and ensuring that the archival versions moved offline are the correct versions of the data.

Storage-virtualization technologies, though not yet commonplace, are rapidly becoming a much more critical part of business computing, from small-to-midsized businesses (SMBs) to enterprise-class environments. But the most important thing for customers to consider when selecting vendors that provide virtualization solutions isn't the classic speeds-and-feeds data but the capabilities and usability of the management solution that accompanies the virtualization product.