Ed note: This is the first in the series of three articles on virtualization from First Data Corp's Sr. Information Systems Analyst, Jerome Wendt.
Normalizing the SANHow to KNOW which storage virtualization technology is the right long term choice
In today's complex storage area network (SAN) environment, one of the most confusing terms to many in this space is the oft quoted but often misapplied term: virtualization. Complicating the matter is that it can be referred to as either SAN virtualization or storage virtualization. As a final twist, vendors tell us this virtualization can reside at the host level, the network level or the storage array level. Of course, they all say their method is the best method and will win out over all of the others.
So what is an overworked systems manager with limited knowledge on the subject matter to do with yet another six-syllable technology? Because ultimately, a wrong choice of this technology could cost you time, money and worse yet, in this economy, your job. But the right choice could mean found time and result in a promotion. Surprisingly, to arrive at the answer to the right choice of virtualization technology, one needs to use a basic relational database design technique, normalization.
To begin with, let's define the terms introduced earlier and then arrive at the logical answer. First, let's analyze the two different virtualization phrases: SAN virtualization and storage
Frankly, SAN virtualization is a meaningless term. Virtualizing a SAN could translate into any number of concepts. Since a SAN encompasses the entire data path from the time the data leaves the server until the data returns from the storage, one could conceivably virtualize any part of the SAN, whether it is the server, the switch or the storage. So the phrase 'SAN Virtualization' is too vague of a term to be used in this environment.
For the purposes of this article and to keep the concept clear, only the term storage virtualization will be used. It truly has meaning and conveys what the purpose of virtualization in a SAN is, to present physical disk volumes in the storage array as a logical entity to the server.Check out Part II where Jerome defines the various and most common types of virtualization: host based, network based, and array based virtualization.
About the author:Jerome Wendt is a Sr. Information Systems Analyst for First Data Corp. He is responsible for Managing and resolving performance related issues. Jerome is also responsible for exploring new SAN and open systems storage related technologies to solve business and technical problems in the data center.
This was first published in September 2002