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Storage virtualization -- V is for victory
By Tony Asaro
12 Aug 2005 | SearchVirtualStorage.com
There are NAS and SAN virtualization products that allow customers to consolidate management of multiple systems, implement intelligent tiered storage, extend the life of existing storage systems and centralize data protection.
To illustrate the impractical nature of discrete storage systems, let us examine a real world comparison of parking garages at an airport. There are four parking garages named A, B, C and D:
If the driver is in a hurry and absolutely requires the fastest access, then he or she will park in Garage A, even at a premium cost. If speed is not of the essence but cost is more important, then long term parking provides the best value. And for many drivers, Garage B and C offer a good compromise between convenience and price. Each driver can choose which garage makes the most sense for them. One day, a driver may need to use Garage A because they are in a hurry or are only going for a day trip and will return later that evening. Another time, that same driver may want to park in Garage D because he or she will be gone for over a week.
The above example is very similar to the way that data storage is implemented. Customers may have multiple storage systems that are dedicated to a specific application or applications. And as that storage system fills up, it cannot share the resources of the other storage systems in the data center. Instead, more disk drives have to be added to it even though another storage system across the room may have a large amount of unused capacity.
Storage virtualization enables intelligent tiered storage, creating one large virtual storage system. Data can be moved transparently from one physical storage system to the other based on cost, capacity utilization and performance as needed.
So let's go back to the parking garage example. You park in Garage A because you are going a day trip. However, your plans change and you have to stay an extra week. Storage virtualization will move your car (data) from Garage A (expensive high end storage system) to the lower cost Garage D (low cost storage system). Additionally, when you get back your car will be exactly where you parked it in Garage A, but you will pay the lower cost (Garage D prices) for your extended stay. That is one of the core benefits of storage virtualization -- creating an intelligent tiered-storage environment that is transparent to users.
Storage virtualization doesn't just drop in and magically solve all of your problems. There has to be a great deal of analysis and planning. However, you can implement storage virtualization in stages. There are some customers who start out slow and incrementally implement. There are other customers that re-architect their entire storage network. And there are many points in between these two extreme approaches.
One of they key objections I hear concerning storage virtualization is that there is a single point of failure (SPOF) for all of your data. When evaluating any storage tool that is supporting mission-critical applications, you have to make sure that the system has no SPOF. Additionally, you might want to consider implementing disaster recovery for mission-critical applications. This is true whether you are using a storage system or a storage virtualization tool. Customers are consolidating multiple last-generation storage systems into next-generation storage systems that are bigger and faster. Any concern of SPOF applies to a single storage system that is being used for consolidation. Consider a storage virtualization tool as a way to consolidate storage systems, but with more options for creating a tiered-storage environment that could save you a ton of money.
Implementing storage virtualization doesn't have to be an all or nothing proposition. You can still have other storage systems that are independent. Also, think about having two storage virtualization products. They can even be from different vendors. That takes care of the other big objection to storage virtualization: Having a single vendor manage all of your storage.
About the author: Tony Asaro is the senior analyst for Enterprise Strategy Group.