Information departments have a mandate to increase operational efficiency and services at a reduced cost while at the same time maintaining more applications, and supporting more users.

A method to achieve this is called virtualization. Virtualization allows a physical server to be divided into several virtual servers each appearing to the applications running in them as if the virtual machine (VM) was a physical server. This has several advantages:

• Scalability - Virtual Machines can be reduced, added or reconfigured as needed
• Efficiency - Servers can run at peak capacity
• Economy - Less equipment, space, and cooling costs and easier management
• Reliability - Virtual machines can be configured to take over loads or replace failed application
• Ease of use - Virtual machines can be centrally managed

Intel® Virtualization Technology can help to contain costs by increasing the potential of consolidating computing resources into less physical devices and automating their management.

The Intel approach of hardware-assisted virtualization using Intel® Virtualization Technology (Intel® VT) provides hardware assistance that enables virtual machine solutions to operate more efficiently, be managed more effectively, and be developed more easily and quickly.

Virtualization’s basic use was to achieve better utilization of hardware and manage software heterogeneity. With technology breakthroughs like Intel® VT virtualization technology hardware from Intel and software from vendors like VMWare*, XEN*, RedHat*, Novell*, XenSource*, and Virtual Iron*, and the availability of powerful, VM supporting multi-processor hardware this is changing.

A virtualized server can now provide the required isolation between VMs making sure a problem on one VM does not affect the others while making better use of available processor, memory, and I/O resources. You can have similar functionality and performance while simplifying server management, saving energy, HVAC capacity, reducing the physical server footprint, and efficiently using all resources.

Virtualization replaces the need for installing more servers and improves IT capability and flexibility. There are many use cases that show how virtualization can be implemented. One use case of virtualization is tier consolidation. 

As the term applies to sports stadium seating, a tier is a layer. In a computer system a tier is a level of service or a functional module of software architecture. Typical tier architecture is the three-tier architecture as with an SAP R/3 or Oracle CRM system.

The user interface, functional process logic, and data storage tiers are independent modules, and, until now, most often on separate platforms. This allows many clients to use the interface to gain access through the process logic to the database layer. The basic rule of three-tier architecture is the client interface tier never has dire ct access the data tier. All communication must pass through the application middleware tier.

The user interface presentation tier, also called the presentation, client, or front-end, interacts with the user. This tier processes user input, requests data, displays results.

The second functional process logic, or application tier, is often referred to as middleware. It processes client requests. It performs all functionality specific to the application but does not store persistent data. This in itself may be comprised of several sub layers of middleware which is termed a multi-tier or N-tier architecture.

The third tier is the data storage or database tier. This tier contains the database management system that stores and manages all persistent data. This is typically accessed through an SQL interface.

The advantage of multi-tier client/server architecture includes:

• Changes to the user interface or to the application logic are largely independent from each other. One application layer can change to meet to meet new requirements without affecting the other.
• Network traffic is minimized by the application layer restricting only the required data for the task to the client.
• The client is insulated from database and network operations and does not need to know where the data is or other details.
• The tier organization database independent; the data layer is written using standard platform independent SQL.
• The application layer can be written in any language that fits the developer’s needs.

Intel® VT technology based virtualization solutions enable you to consolidate more applications on fewer physical servers, avoiding costly data center expansion and lowering management costs.

As stated earlier, each of the tiers would usually be located on its own dedicated machine for performance, availability and security reasons.  In many cases, it is practical to merge different tiers into the same server. For example, database and application server tiers can be run from virtual machines on the same server or physical system. This reduces hardware procurement and operation costs, lowers cooling expenses, shrinks data center real estate requirements, and eases server management and better utilization of computing resources.

Tier Consolidation could follow two or three strategies. If the database tier is large and complex and the network access traffic from the middle layers was heavy, the database would likely remain on its own physical machine for performance reasons and the application servers (middle tiers) which access the database tier would reside on a consolidated platform running unchanged in a virtualized environment.

The second configuration for a Tier consolidation usage model is to combine database and application tiers each on separate VM on the same physical machine. Choosing to virtualize the database depends on many factors but, in general, the simpler the database the more likely it would be a candidate to be virtualized.

The third configuration has the client interface, database and application tiers each in a separate VM on the same machine. The client tier would be a thin client server like Citrix* allowing one instance of the client tier software to serve all users.

In heterogeneous virtual tier consolidation each VM on the physical system is running a different tier (or even two tiers in a single VM). A homogenous virtual tier consolidation has a server hosting multiple VMs each running the same application tier.

Heterogeneous and homogenous virtual tier consolidation can be combined. As an example a three tier architecture application and a 16 CPU server could be configured into a 4-CPU database virtual machine, and three 4-CPU VM application middleware tiers. The DB and application tiers are consolidated on the single machine (a heterogeneous consolidation in this case), but you also have multiple application tier instances consolidated into same physical machine (homogenous consolidation).

Such virtual configurations offer maximum cost savings, efficiency, flexibility, scalability, and ease of system management.

Using virtual solutions on an Intel® VT hardware platform allows more efficiency, flexibility and simplifies design and management. Virtual consolidation of a client-server or multi-tier application has these advantages:

• Only the hardware changes
  • Virtual machine configurations change, not the software.
  • Applications can run on fewer more powerful servers (like those with the Intel® “Caneland” quad-core processor) hosting multiple virtual machines and combine multiple tier instances onto one server
  • Client, application, and database servers can be combined on a common virtualized server
• Redundancy reduction
  • Reduce the number of instances of a tier to process a given workload
• Significant reduction in operating cost
• Significant reduction in software license cost
• Less space and facility costs
• Environment easier to manage
• Improved security
• Greater availability of applications and data
• Reduced maintenance
• Dynamic or rapid provisioning
  • As more load capacity is required, an appropriate tier can be instantiated in a VM dynamically. For example: Automatically instantiate additional application tier VMs at peak periods.
• Load balancing and failover (migration) can be facilitated through virtual tier consolidation – as it would with general application consolidation uses.

With the improvements made to virtualization technology supporting hardware by Intel® VT and software performance and ability improvements made by virtual solution vendors working with Intel what was only desirable is now available: The consolidation of high performance multi-tier architectures on virtual machines. Intel is working to provide a wide range of platforms supporting virtualization technologies.