The virtual appliance marketplace includes products that can be utilized for several different purposes -- they can optimize existing storage or be used for backup purposes. At the very least, virtual storage appliances provide what looks like shared storage without additional hardware by creating a virtual pool of storage from unused direct-attached capacity. In this podcast, Microsoft expert Brien Posey also explains how the concept of products in the virtual appliance marketplace can go beyond primary storage to other uses such as virtual appliances for data protection.
Can you tell us about the key benefits and drawbacks of virtual appliances?
Brien Posey: There are a lot of benefits. The biggest one is probably that you don't have to buy a dedicated physical appliance. That typically saves a lot of money because, as we all know, high-end appliances aren't cheap. In some cases, the virtual storage software is even free; there are free versions out there for low-end use. Also, scalability and performance tend to be benefits, which wasn’t necessarily the case not too long ago. First-generation appliances really didn't scale all that well or perform nearly as well as physical appliances, but that is starting to change -- sometimes you would be hard-pressed to tell the difference between the scalability and performance of a virtual appliance [and that of a physical appliance]. Also, with virtual storage appliances, you tend to get the same feature set as a physical appliance.
As far as the drawbacks, there aren't many, but there is one big one: With a physical appliance, you basically just buy what you need and you're done. With a virtual appliance, you need a lot more planning because you have to evaluate the underlying physical hardware to make sure it can meet the demands of the virtual storage appliance environment you're going to be running.
One of the main reasons people look to virtual appliances is for data protection. Do you think virtual appliances for data protection and those for primary storage are different classes of product?
Posey: I think it depends on who you ask. Obviously, the vendors would tell you they are. What you have to look at though is the underlying core appliance. [It] is generally the same for a general primary storage virtual appliance versus a data protection virtual appliance. Typically, the core is identical between the two, assuming they're from the same vendor. They have a lot of the same underlying features, but your data protection virtual appliance is going to have certain features geared solely toward data protection. So I guess if you look at it that way, yes, they are different classes of product.
What would you say are the main differences between virtual appliances for data protection and those for primary storage?
Posey: It's obviously going to depend on the vendor, but you have to realize that with primary storage appliances, if you go low end then you're just going to get a very basic feature set. If you go with a commercial-grade primary storage appliance, it is going to come with a certain feature set that is geared toward an enterprise or at least medium-to-large business environment, and that feature set almost always carries over into backup appliances. So if you buy a virtual appliance designed for backup, you're going to get a lot of the same features you would for a general-purpose storage appliance, but you're also going to get some features geared solely toward backup. Specifically, a lot of the backup storage appliances are designed to act as cloud storage gateways so data can be replicated to the cloud, and that's typically something you don't get for just a general-purpose virtual storage appliance.
Brien Posey is a Microsoft MVP with two decades of IT experience. Before becoming a freelance technical writer, Brien worked as a CIO for a national chain of hospitals and healthcare facilities. He has also served as a network administrator for some of the nation's largest insurance companies and for the Department of Defense at Fort Knox.