Chapter12.Storage Virtualization: The Power in Volume Management Software and SAN Virtualization Systems

Chapter 12. Storage Virtualization: The Power in Volume Management Software and SAN Virtualization Systems

Upon completing this chapter, you will be able to

• Participate in meetings and planning sessions about storage virtualization strategies and products

• Participate in evaluations of virtualization products

• Discuss the benefits and risks of virtualization products with coworkers and vendors

• Describe the differences between volume management and SAN virtualization systems

The manipulation of storage address spaces through storage virtualization technology is certainly one of the most important enabling technologies in storage area networking. In fact, it can be argued that all working SANs make use of some form of virtualization and that the value of the storage area network (SAN) is related to the extent to which it is applied to manage SAN resources. However, what this means in terms of products and architectures is a matter of opinion for the time being, depending on one's involvement with specific products and strategies.

A few years ago it was difficult to find SAN products that were not marketed on the strength of their storage virtualization capabilities, even if the application of virtualization was somewhat trivial and the benefits existed only in sales presentations. Unfortunately, all the noise over storage virtualization made it difficult to understand what it was or how it could be most effectively used.

This chapter explores the mechanisms of storage virtualization and its implementations in two different types of products: volume management software and SAN virtualization systems. The use of Redundant Array of Inexpensive Disks (RAID) technology, the topic of Chapter 9, "Bigger, Faster, More Reliable Storage with RAID," is assumed with any storage virtualization product, as are the concepts of subsystems (see Chapter 5, "Storage Subsystems") and Small Computer Systems Interface (SCSI) (see Chapter 6, "SCSI Storage Fundamentals and SAN Adapters").