Virtualization – Not just for large businesses – Part 1 of 2
Lower long term costs and increase IT effectiveness through virtualization.
Traditionally, firms deploy several servers each with a unique function as outlined in the diagram below.
Figure 1 – Traditional Server Deployment
In Figure 1, a firm has a BlackBerry, Database, File and email server running on 4 separate physical servers. Depending on the size of the firm and the load placed on the servers, one can expect these servers to cost $2,500, $6,000, $6,000 and $6,000 respectively for a total hardware cost of $20,500 if purchased outright.
If one physical server were purchased instead to house the four servers above, the diagram would change to the one in Figure 2. One, larger server is purchased, perhaps with 6 network cards and 16GB of memory and 2-4 processors. The virtualization software allows the network administrator to allocate the appropriate resources to each server so that the resources are balanced and meet the needs of each server.
Each virtual server operates in the same way that it would if it were a separate physical server. This is the simplest model and provides the following benefits:
- Lower Energy Costs
In the above example, one server is used instead of 4, significantly reducing the costs for power and air conditioning associated with running the server.
- Lower Maintenance Costs
With fewer servers, there is less to maintain. Also, the life span of the physical server is extended when used for virtualization since limiting resources such as memory, network cards and disk can all be added without affecting the end users.
- Smaller Footprint
The space required to house the server is much, much less. In some cases, the space savings may allow the server room to be repurposed or serve additional purposes without impacting the operation of the server system.
- Room for Growth/Application Testing
Suppose the application PC Law is not operating quickly enough in the firm’s environment; a new virtual server could be created and deployed dedicated to PC Law. This would improve the performance of the application and allow for fine tuning the performance of the application to meet the needs of the firm.
- Better Disk Utilization
With individual servers, more disks must be purchased per server resulting in wasted space on some servers and overuse on others – if the space is not planned out just right. With virtualization, the allocated disk does not need to match the real disk available, meaning that disk space can be expanded or contracted as needed on a given virtual server from the physical pool of disk resources.
- Application Isolation
If desired, servers performing multiple functions can be stripped of excessive functions and separate servers can be deployed for each function. This minimizes cross application conflicts thereby making the system more reliable.
- Server Templates
Once a server is built, it can be templated, meaning that additional servers can be built from a standard basic model. Because of this, new servers can be deployed much more quickly than with a traditional system.
Snapshots allow updates to the operating system to be applied with a separate delta file. Thus, if the update causes problems with the server, the virtual server can immediately be rolled back to its prior stable state. If the upgrade is successful, the snapshot can be rolled into the existing virtual machine, making it a permanent part of the build for that virtual machine.
Figure 2 – Virtualizing Traditional Servers
The cost of the virtual server would be about $7,000 in this example. VMware software would be about $4,000 and disk storage about $5,000. Thus, under this model, the hardware cost would be about $16,000 – somewhat less than the hardware cost of traditional servers.
Improving Redundancy and Reliability
In the previous example, the minimal requirements for virtualization were considered. However, in a proper implementation, it is desirable to ensure there is no single point of failure. While this is more costly initially, in the long term it provides the firm with a more robust solution.
In this second example, we add a second identical physical server and split the virtual servers between them. The two servers share the same disk resource and thus, if one server fails, the other can pick up where it left off and end users are not affected by the outage. This capability is provided by the virtualization software. The configuration is shown diagrammatically in Figure 3.
Figure 3 – Fully Redundant Servers
This configuration adds the following benefits to the virtualized environment:
- Automatic Failover
If one physical server fails, the virtual servers immediately start up on the other physical server. This is facilitated through the virtualization software. Thus, hardware problems will never cause service to be unavailable to members of the firm. By design, the system is set up so that all virtual servers can run on a single physical server.
- Application load Balancing
While two virtual servers are shown on each physical server above, that number is arbitrary. The number of servers located on each physical server is entirely subject to the load to be placed on that server. Thus, there could be 3 servers on Physical Server 1 and 4 servers on Physical Server 2. Thus, virtual servers can be deployed to maximize the use of each physical server.
Down Sides of Virtualization
Every technology has its downfalls and virtualization is no exception. Some include:
- Increased Software Costs
Because of the propensity to take advantage of the ability to deploy additional servers where a decision to purchase a new server might not have been made, software costs for Windows licensing may increase. Virtualization software is also another layer of software that must be purchased for the system to operate, thereby higher costs.
- Application Compatibility
Some older applications are not compatible with virtualization. They are few but they do exist.
- Production Environments must be Built by Professionals
Unlike standard Windows systems which can be built by anyone with a little server skill, virtualization requires proper planning and optimization of all components within the system. A firm should never try to deploy virtualization on its own unless it has in house virtualization specialists.
- Troubleshooting can be more Difficult
A virtualized system is more complex. As such, it can be more difficult to diagnose an issue than with a standard system. However, the virtualization software has many more tools to assist in diagnosis than standard Windows. As such, there may actually be advantages to having it from this perspective.
- Server Sprawl
In an unmanaged environment, there may be the tendency to create a lot of virtual machines without due consideration for the entire environment. This can result in a lot of servers being created which may not be necessary. This is why we recommend that virtualization be done by professionals skilled in these types of deployments.
These drawbacks are relatively minor. Virtualization is a time tested and proven method of achieving all the benefits listed above and can extend the life of your server hardware significantly over traditional systems. If your firm is looking to upgrade its server technology, we would urge you to consider virtualization.