The Value Of Virtual Appliances

Vendors created the appliance market by delivering their software applications pre-installed on standalone servers. The goal was to simplify installation for the users and to make support easier thanks to the consistent hardware platform. The downside to appliances is that there is an added hardware cost and when performance needs to be upgraded it often requires a new appliance. These issues can be addressed by leveraging server virtualization to create virtual appliances.Virtual appliances are pre-configured software applications delivered as a virtualized server image. To get it going all the virtual administrator has to do is copy the image in to place and start the virtual machine. Most of these appliances will kick off a configuration wizard that will walk you through the setup process the first time they are started. The virtual appliance concept is gaining in popularity. There are appliances across the spectrum of data center services ranging from file services, as we will discuss in our upcoming webcast "Adding Virtual NAS To Your SAN By Leveraging Cloud Storage", to WAN Acceleration to even virtual backup servers.

The value of delivering services this way is that it drives down the complexity and cost of the implementation while at the same time maintaining the hardware consistency that makes the support job easier for the vendor. In fact in some ways it even makes implementation easier since no additional space and connections need to be set up to accommodate a new physical hardware component. It also provides greater hardware flexibility, if you need more or less performance for that particular appliance then you can move the virtual machine with the hypervisor's migration capabilities to a new physical host.

The other problem that virtual appliances fix is the problem of appliance sprawl. Because the appliance concept has become so popular everything from file services to WAN optimization is available in a appliance form factor. In many data centers this has lead to racks of appliances all on their own physical hardware using very little of the resources of that hardware. This also leads to a server mix that makes data center managers cringe. If you have a contract with server vendor A, it is frustrating when the turnkey appliance is sent to using hardware from server vendor B.

Virtual appliances let you gain all the preconfigured advantages of appliances without taking up racks of data center floor space and mixing in alternate server vendors. The real advantage is the ability to easily re-deploy the virtual appliance to a faster more capable box if the need arises. Virtual appliances are a favorite in our labs, they make testing easy and then moving to production is a simple VM migration. We have gone so far as making a virtual appliance a requirement for us to test a new product.

The value of virtual appliances is unmistakeable, deciding which type of appliances are best suited for the virtual world and how those appliances will impact your virtual infrastructure will be the subject of our next entry.

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George Crump is lead analyst of Storage Switzerland, an IT analyst firm focused on the storage and virtualization segments. Find Storage Switzerland's disclosure statement here.