Consolidation's a Good Place to Start Virtualization Planning

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AS OF 1/7/2009 6:30AM EST

Consolidation's a Good Place to Start Virtualization Planning
By Lisa L. Morgan

June 10, 2008 — Virtualization is such a hot topic even business magazines are writing about it. Despite the buzz, virtualization can and does pose a number of challenges to IT professionals and data center managers that can be minimized by understanding the issues and using the right tools.

Before starting any IT project, it’s a good idea to have a sound plan in place, although not all shops have them. It may be that one department or office decides to consolidate servers in an effort to reduce rack space, power consumption, cooling and underutilized boxes. Or, it could be that IT, the data center manager or both are taking a long-term view about the strategic advantages virtualization can deliver. What you want to accomplish is a good place to start and it may change over time.

Quite often server virtualization begins with consolidation, but later other benefits become obvious such as business continuity, disaster recovery and fault tolerance.

“Consolidation is like a diet,” said Rebecca Austin, director of virtualization consolidation at IBM Systems and Technology Group. “It reduces overhead, [but as] new systems and hardware are added, bloat creeps back.”

Ironically, one of the reasons to consolidate servers is to put an end to server sprawl. At the same time, virtual machine (VM) sprawl can and does happen, which—depending on one’s perspective—is or is not a problem.

VM sprawl isn’t a problem if you take the view that several VMs can reside on a physical server. On the other hand, VM sprawl may be a problem if you consider the potential software licensing issues that may arise—especially given the ease and speed at which virtual servers can be deployed.

Vijay Sarathy, senior director of Sun xVM marketing at Sun Microsystems, said that the most insightful professionals look beyond consolidation to “bells and whistles,” like disaster recovery, because that makes virtualization more cost effective.

Another issue is who owns server virtualization? The CIO or CTO? A line-of-business manager? Data center managers? Systems managers? And what about network managers and storage managers?

“It varies in enterprises [and] depends on where the decisions are being made,” said Austin. “Depending on the goal and reach, it can be a line-of-business manager or the CIO/CTO, but typically the CTO is closer to the pain and spends more on infrastructure [and so is often] responsible for the budget.”

David Lynch, vice president of marketing at Embotics, said server consolidation sometimes creeps through the back door because the culprits are trying to reduce hardware-related costs.

“When consolidation happens, the operations group, data center manager and line-of-business manager all own pieces of it,” he said. “We ask how many virtual centers [exist] because so many people want to control it.”

It’s hard to have a plan that will benefit the entire enterprise when consolidation is occurring in an ad hoc fashion.

Sun’s Sarathy said that in his experience small departments generally aren’t the source of initiatives. Instead, the decision is typically driven by IT.

Either way, without upfront planning, it can be more difficult to move past simple consolidation to more sophisticated forms of virtualization, such as business continuity or disaster recovery.

A good plan should begin with an assessment of current resource utilization patterns, security implications, and internal and external service level requirements, and should include policies and processes.

“Sometimes you can run into an application quality issue if you don’t understand how applications will run in a virtualized environment,” said Sarathy. “You should also decide how you want to structure storage.”

Deploying VMs
The good news is that VMs can be deployed almost instantaneously. The bad news is it may be difficult to keep track of them over the life cycle, and not all application vendors may support them, which may cause licensing, compliance, reliability and performance issues.

Joe Brown, president of Accelera Solutions, said part of the problem is naiveté—that is, some vendors have little or no experience with VMs and therefore do not claim to support them. Alternatively, some application vendors believe VM-based licensing will have a negative impact on sales.

“When you take away physical servers, people get nervous about losing something,” he said. “It’s cultural.”

And it’s not just vendors that get nervous about the inability to see boxes. When physical servers are deployed, they can be managed by walking around. You can’t see VMs simply by standing in front of a rack, however.

Then there’s the question of who is deploying the VMs. IT professionals have typically deployed physical servers but VMs can be deployed by just about anyone—and quickly—because the software has been designed simply so line-of-business managers can use it.

This is bad news for IT and data center managers who worry about loss of control. Unless there are policies and procedures in place governing who will deploy, manage and maintain virtual servers, challenges can arise such as VM sprawl, software licensing issues, security issues and storage issues.

Sun’s Sarathy said one of the main problems has to do with complexity. The deployment of physical servers results in linear growth while the deployment of VMs can result in geometric growth.

“Before you had to deal with one physical server [at a time],” he said. “Now you have to deal with a physical server that has n virtual machines which creates geometric complexity.”

Then, of course, there are usually multiple operating systems and sometimes multiple versions of operating systems, a plethora of applications, and device drivers in the environment, which is why IBM’s Austin said having internal standards for footprints, operating system versions and applications is important.

Two types of applications that have been slow to move into virtualized environments are mission-critical applications and high I/O applications. As for running mission-critical applications, there are two things to consider: the physical server itself and the state of the art.

Virtualization is actually a mainframe concept. IBM and others have virtualized all kinds of servers from high-end mainframes to cheap x86 servers. Enterprises have been slower to run mission-critical applications on x86 boxes mainly because, historically, they haven’t had the same level of built-in availability, security and fault tolerance that higher end machines do. However, given the speed, security and redundancy improvements made to x86 machines more companies are running mission-critical applications on them, server sellers say.

Most organizations start consolidating non mission-critical systems like file servers and then work their way up over time.

In many cases, high I/O applications are still better left on dedicated machines, assuming their resource utilization rates justify it. Heavy video and design applications may also remain tied to physical servers.

“Very few workloads are not amenable to virtualization,” said Simon Crosby, CTO of Citrix’s virtualization and management division and a co-founder of XenSource (which Citrix acquired). “The exceptions are I/O intensive applications and [situations in which] the application vendor has not certified the application [to run in a virtual environment].”

Over the next year vendors anticipate more heterogeneity as it relates to hypervisors. At present, VMware is the undisputed leader with market share estimates ranging up to 80 percent. However, both friends and foes expect Citrix, Microsoft, Oracle, Sun and others to gain traction in the coming months.

“Next year, most organizations will be heterogeneous,” said Embotics’ Lynch.

Storage is another consideration. Should you use NAS, a SAN or local storage? It depends on volume. Some say you can start with local storage and grow later. Others say it is better to have parallel consolidation/virtualization and storage strategies.

“Storage is a big question,” said Crosby. “As the number of VMs goes up, storage becomes critical.”

When there is a data center but no SAN, it’s possible to start a consolidation initiative using on-board storage. But if the organization is moving past consolidation, it’s better to have a SAN in place because backup is easier and VMs can be moved faster, said Lynch. There are also concerns about failover and load balancing.

Apparently the financial institutions Citrix is working with have been using the same process to deploy physical servers and virtual servers. The good news is they maintain rigid control, but the control has cost them flexibility in mobility (moving virtual servers from one physical server to another) and reconfiguring resources on demand.

“The biggest issue is the fear of losing control,” he said. “Data center managers don’t like it when they’re not in control.”

Lynch also stresses the importance of virtual machine IDs because it enables the tracking of VMs.

“If I can identify a virtual machine I can control mobility and enforce policies automatically,” he said. “The issue is starting to get more business press and the side effect is that auditors are waking up [and] downloading white papers.”

Systems Management
Are virtual servers easier or harder to maintain than physical machines? It depends on whom you ask. Some say they’re harder to manage because the management tools aren’t mature enough yet. Others say management is easier mainly because virtual servers are actually software and so patches and updates can be aggregated more simply.

Some hypervisors include management functionality or at least interoperability with established systems management tools that are increasingly capable of tracking VMs. Citrix’s Crosby said when a hypervisor has its own functionality and there is another systems management layer in place, the two management layers “can get tricky.” As a result, Citrix integrates with third-party management tools rather than providing a competitive suite of independent management products itself.

Embotics’ Lynch said two main problems his customers face are lost server ID and state changes.

“In a moment you can create a virtual server with a click of a mouse, but it can be hard to track as most management systems have been built for [stationary] physical servers not virtual servers that [may] move around,” he said. “Virtual machines can also change states, and when they’re offline it can confuse the management software.”

He also said when a VM moves, the management software may count it twice.

Generally speaking, there’s a lot of room for improvement when it comes to tools because customers still aren’t getting the kind of life-cycle visibility and control they need despite what any one company may say or name a product. As more standards are adopted and technology improves virtual systems management will become less of an issue, but in the meantime, established players and start-ups alike will enjoy a lucrative playing field.

Sun’s Sarathy said companies are still grappling with information silos resulting from disparate management applications that require standards and APIs to overcome.

“Multiple tools need to be tied together [because] no single tool does it all,” he said.

As visibility remains a challenge, and at the same time practically anyone can deploy VMs, companies often end up with a proliferation of VMs that don’t necessarily create resource problems but could result in software licensing issues.

Part of the problem with existing software licensing models is they haven’t kept pace with the trend toward virtualization. Quite simply, per user and per CPU-based pricing doesn’t work in a virtualized environment. Even when software licensing is decoupled from hardware, problems can arise especially since virtual servers can be set up and torn down in a single day.

“Very few vendors have an answer about how licensing [works in a virtualized environment],” said Lynch. “You can turn 117 servers into virtual machines without making any changes to applications, but nine months later you’ve got 342 virtual machines.”

And without the right management tools, it can be difficult to track VMs, OS instances and applications, particularly when VMs are being moved from one physical server to another.

One of Embotics’ government clients purportedly “hates” virtualization because employees are downloading virtual appliances and putting them into production. After the fact, the need for licensing arises. Part of the problem is that the customer is not keeping track of the number of VMs he or she has, and the worst part is the customer is not unique.

So, as it relates to licensing, there are two problems: whether the OS or application vendor is licensing in a manner that contemplates VMs and whether the end customer is even aware of the number of VMs that exist. The blind proliferation of VMs may result in additional licensing costs as they relate to OS instances and applications. Some say the additional software costs could unnecessarily offset hardware-related savings in the absence of sound VM tracking.

Lynch and Sarathy also view security as a problem because hypervisors and VMs represent a new and rich type of attack vector. If a hypervisor were compromised, a hacker could target all the VMs below it, they say.

Crosby disagrees. He said the threat is more hypothetical than real at this point.

However, it’s already possible to run into issues if the SAN is compromised because VMs reside on it and there are data connections to the network, said Accelera’s Brown.

Decommissioning Servers
Usually a physical server is decommissioned in two or three years, not because there’s necessarily anything wrong with it, but because more powerful technology is available at a lower price point and in a smaller footprint that requires less power and cooling. Or perhaps the warranty is about to run out. By contrast, some say there’s no good reason to decommission a virtual server.

When a physical server is decommissioned it doesn’t create a problem for virtual servers because the virtual servers are simply moved to another box.

“Tearing down virtual machines doesn’t happen very often,” said Embotics’ Lynch. “One customer turned off 70 percent of its virtual machines and waited for people to scream. Some never did. The more virtual machines you have, the harder it is to spot a rogue [one].”

Decommissioning virtual servers is a different matter, however. First, they need to be located and, assuming they can be, someone has to decide whether decommissioning actually makes sense. After all, the physical space is available essentially for free, but again, that’s just hardware.

If a virtual server faces performance problems due to overcommitted resources it might be decommissioned, said Sun’s Sarathy. More likely, the virtual server would be moved to another physical server capable of handling the workload. If, on the other hand, the application is no longer needed, the workload might be decommissioned and the VM deleted to free up the associated storage space.

Bottom Line
Although it’s possible to consolidate or otherwise virtualize servers without a plan, it’s inadvisable over the long-term. In a lot of instances, it makes sense to start consolidating non-essential servers and then move into more sophisticated forms of virtualization over time. Nevertheless, vendors recommend having a long-term plan that contemplates current demands on physical resources as well as long-term business and IT objectives.

From an everyday perspective the devil is in the details as application availability, resource utilization and allocation, security, storage and redundancy should not be overlooked.

VMs are quick and easy to deploy, but management tools and licensing haven’t kept pace, although newer tools are providing better visibility and software vendors are beginning to adapt their licensing strategies to suit virtualized environments.

The coming year will bring yet more advances in hypervisors and systems management tools. In the meantime, sound systems management judgment won’t go out of fashion.

Related Search Term(s): Data centers, virtualization, Citrix, IBM, Sun

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