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March 12, 2010
Vol.32 Issue 6|
Page(s) 12 in print issue
Server Virtualization Explained
Save Money & Resources With Fewer Machines & Less Infrastructure
Small to medium-sized enterprises are still early in the adoption curve following the introduction of server virtualization a few years ago. However, as the technology matures, more and more SMEs are considering a move to server virtualization. Here is a look at how the technology can significantly boost server operations as well as some things to know in order to get the most out of virtualization, whether your enterprise is virtualizing server environments for the first time or has only consolidated a small percentage of its servers.
• Consolidating machines into a single server through virtualization offers direct reductions in hardware and electricity costs, peripheral hardware needed to maintain the servers, and space requirements.
• Server virtualization requires specialized human skill sets, which can, especially in the beginning stages, require more manpower.
• Virtualized servers involve specific maintenance requirements compared to other types of virtualized hardware.
The Business Case
The underlying concept of how virtualization can boost server efficiencies is simple: Many physical servers can be consolidated into a single physical machine while continuing to operate as separate yet virtual servers. In some cases, virtual machines can share operating system kernels, but the consolidation of standalone server machines remains the predominant application. The benefits are tangible, because with virtualization, the number of physical servers is divided by 10 to 15 on average, which represents a significant reduction in hardware and associated equipment, power consumption, and space requirements, says Eric Maillé, capacity management consultant for Systar (www.systar.com).
“Before virtualization, IT administrators spent about 60% of their time [on] maintenance, support, and other tasks to maintain an infrastructure at the same level,” Maillé says.
Besides consolidating physical servers into a single machine, virtualization can help cut down on the amount of time admins would otherwise have to spend when building a new server environment. “Many organizations cannot go from start to finish when ordering and provisioning a server in less than three months. A physical application/server relationship is therefore a major business problem requiring a new application and therefore a new server,” says Clive Longbottom, service director of business process facilitation at Quocirca (www.quocirca.com). “Virtualization allows this to be changed—multiple applications can be shared across a physical server asset base. This not only frees up the spare resources that will be found sitting around unused in a physical app/server environment for actual valuable usage, but also enables applications to be run in a far more business-continuous way through mirroring and failover capabilities.”
Virtualization, for example, allows for duplicate images of servers to be made, usually in a cluster configuration, so in case of a breakdown, the same virtual server with updated data and applications can be up and running in a few minutes. The concept is similar to redundant RAID configurations that protect data by mirroring it across different disks so that data is not lost if one fails. “The operating system can be sitting there as a ‘golden image,’ meaning the same image is used for every new instance of a server, complete with the latest patches and service packs,” Longbottom says. “This can also include the app server plus anything else the IT [staffers] want and, once available, can be pushed over onto a virtual server with great ease.”
Fewer Servers, More Human Skills
It is important to keep in mind that managing servers in a virtual environment requires different skills sets, which, at least initially, command higher manpower costs as staffers learn how to operate the new servers in the virtualized environment. “With virtualization of servers, you are adding a new layer of technology, so you should expect additional management,” says Chris Wolf, an analyst for the Burton Group. “Organizations often virtualize first and worry about management later, which creates problems that proper planning can avoid. Vendors encourage organizations to go ahead and virtualize, but in reality, organizations realize that virtualization is different and has different requirements.”
The bottom line is that virtualization will not save on staff headcounts, especially in the beginning, Wolf says. “Virtualization can require more staffers,” he says. “There will not be fewer administrators because the number of servers is just going to be the same even though they are virtual. In reality, the [amount of administrator work] will only increase, because in addition to the physical servers that have become virtual servers, you are going to have all of these virtualization platforms.”
Admins thus need to adapt their management processes to become “virtualization-ready,” involving backup and recovery, disaster recovery, capacity planning, management of virtual disks, and security, says Ewald Comhaire, global practice manager of data center transformation for HP Technology Services (www.hp.com). “For example, a virtual server that is not needed for six months could be rapidly brought down, which is great, but care has to be taken before it can be brought up [again],” Comhaire says. “[The server] must be patched and updated since a dangerous virus or worm may have appeared in recent weeks.”
The Server Specifics
Some admins might be tempted to think of virtualization as an IT department-wide project that will involve the entire infrastructure, including routers and storage, at the same time. Instead, server virtualization involves specific features and management processes. You must thus manage your server virtualization as something separate from your virtualized switches, routers, and other network infrastructure, says James Weir, CTO for UShareSoft (www.usharesoft.com). “It is possible, for example, to only virtualize your servers while maintaining a physical switch and routers,” Weir says. “With server virtualization, you are looking at the part where you have the physical machine running different virtual servers and [sometimes] operating systems. It is definitely a separate aspect of virtualization as a technology, compared to switches and storage.”
Although differences between server virtualization and other forms of IT infrastructure virtualization are not significant, they do exist, Comhaire says. “Virtualization is about separating IT functions (computing, storage, etc.) from the physical devices that are hosting these functions in order to increase asset utilization, reduce cost, and increase business flexibility,” Comhaire says.
by Bruce Gain
Getting Started |
When getting started with a server virtualization project, it is necessary to first check that the hardware of the machine that will house the different virtual severs can handle the computing load and has the capacity. “However, it might not be a linear comparison since you will often consolidate older servers that could be three to five years old into a newer one, which needs to be factored in, as well,” says Chris Wolf, an analyst for the Burton Group.
Secondly, it is not a good idea to port mission-critical servers to a virtual environment when getting started. Installing and managing virtualized servers for the first time require a learning curve, so it is better to discover the technology with less-important applications when the likelihood of things going wrong is high. “Go for low-hanging fruit first,” Wolf says.