Taking Control Of Virtual Machines


VMware vSphere 4.1’s new features act as a referee when virtual machines contend for scarce resources

VMware vSphere 4.1 has a lot more moving parts. Memory compression and the addition of I/O controls for networking and storage, which join those already found in the CPU, are responsible for this increase.

For data centre managers, the new capabilities are a boon. The features basically act as a referee when VMs (virtual machines) contend for scarce resources. The additional moving parts also mean more policy to make decisions that will set out the rules used by these newly minted referees.

Squeezing out productivity

This increase in VM resource flexibility results in a significant growth in the importance of management tools and skills. To stay ahead of the pack when it comes to squeezing productivity out of virtual infrastructure, management tools will gain importance only when virtualisation makes gains in production environments.

This is also true for cloud resources. In fact it may be even more important for cloud-based resources because the decision to spin up or take down cloud-based infrastructure is dependent on automated decision making that must—ultimately will—be governed by the policies people create.

But let me come back to today’s reality. With the release of vSphere 4.1, an update to VMware’s widely deployed x86 server virtualisation platform, data centre managers have greater control over how memory, network and storage resources are allocated among VMs.

Memory, network and storage

Memory compression enables IT managers to determine how physical memory will be apportioned between VMs and the physical host to minimise swapping memory pages to disk. Network and storage I/O controls use policy to give some VM workloads priority over others when there is resource contention.

As of today, these memory, network and storage controls are a first step in the direction of increased flexibility. There will be no turning back from this move toward fine-tuning VM resource use.

Data centre managers who have been touting virtualisation primarily as a consolidation and cost-reduction tactic must now change gears. To maintain the cost savings associated with physical-to-virtual or “virtual first” data centre consolidation plans, management tools are required.

Rocky road

Unrelated to VMware specifically, there are several problems that data centre managers will confront along the road to a fully managed virtual infrastructure.

First, management generates no revenue. When it comes to cost justification, management is second in difficulty only to security tools. At least, management tools can demonstrate their use on a daily basis by generating utilisation reports. Security tools are usually noticed only when they satisfy an audit check box, when they fail and when the renewal bill shows up.

Second, there is a great deal of confusion about the amount of management needed in a virtual environment. A virtualised data centre can reduce the importance of individual hardware failures by enabling workloads to migrate seamlessly. However, that underlying hardware fault must still be corrected to maintain the resilience of the virtual environment.

Thus, it’s not true that data centre managers can just forget about hardware. What has changed is the much lower level of urgency that now needs to be assigned to hardware break/fix operations.

Third, management is a topic that only a mother could love. Management tools force data centre managers to operate at a level of arcana that has not been “consumerised.” There is very little in the management realm that appears magical. And it’s the one area where IT staff must focus only on the negative: What’s broken, failing, overloaded or slow.

Very few people on the business side of your organisation want to hear about how the sausage is made: They just want to enjoy its savory goodness. But somebody has to be the cook, and whether virtualised or physical, cloudy or sunny, that job falls to IT.

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