Since most major vendors now have free hypervisor capabilities, it's easier than ever to virtualise and add machines, but once sprawl occurs it can be costly and tricky to rein in.
IT managers are on the hunt for ways to detect unauthorised, non-compliant changes to their virtual environments and have complete visibility from a single point of control.
According to recent research from consultancy Morse, just over half (51 percent) of U.K. businesses have not had time to adjust their data centre management strategy to meet the needs of their business and virtual environment.
As VMs are easy to create, 67 of the 100 IT directors questioned admitted to not knowing the exact number their organisation had.
Ewen Anderson, managing director of value-added reseller (VAR) Centralis, said many implementations of server and desktop virtualisation start out as small-scale projects and proof-of-concept installations, and are then moved into production because of their ease of use.
"The main issue for the organisation is that if such deployments are allowed to grow 'organically,' they will suffer from three critical weaknesses," he said.
VM sprawl downsides
Anderson said businesses that do not carefully manage virtual server deployment will not have an underlying analysis and design that aligns the virtualised service with the organisation's needs and aims.
Secondly, they will not have been constructed with large-scale maintenance and upgrade as a prime consideration. Third, they will not have had sufficient capacity planning and load testing carried out.
Fredrik Sjostedt, director of EMEA product marketing at virtualisation giant VMware, said managers need to keep a tight grip on what is being deployed just as they would in a physical environment. "When a physical server is provisioned, the IT manager tends to think ahead to four or five years down the line, causing them to over-allocate memory," he said. "This is also a danger in the virtual world, so capacity planning is an important part of any virtualisation strategy."Creating VMs can be useful and efficient, but the IT manager can be left chasing his own tail.
vice president EMEAVizioncore
Giuseppe Nardiello, business development manager at IT resource planning vendor Neptuny, said that in the past, server sprawl was perceived more as a nuisance than a real problem -- but that's changing.
"Basically, it was considered an acceptable trade-off between cost on one side and manageability and resilience on the other," Nardiello said. "Nowadays, it is considered … by many organisations as a serious financial and efficiency problem."
Specific tools have been designed to help customers with server sprawl. Among those tools is Neptuny's Caplan, which gives customers visibility of the performance and cost of their IT infrastructure through simulation models and optimal allocation plans, the company says.
Roger Baskerville, vice president EMEA of virtualisation management vendor Vizioncore, said virtual machines need to be turned off or deleted when not in use.
For example, if an organisation knows its website will be hit with a lot of traffic for a busy time of the year, it can create a new virtual machine to deal with this. However, when that period is over, the machine needs to be turned off or deleted -- not forgotten about.
"Creating VMs can be useful and efficient, but the IT manager can be left chasing his own tail. Initiatives such as chargeback can be introduced so each department keeps on track of their own systems or they are charged," Baskerville said.
Vizioncore's FogLight product turns on a light inside the dark room that is virtualisation and gives the IT manager a better view of what machines they have and who they belong to.
Backing up virtual machines is a problem
New servers are often created for a business or departmental reason when instead, a good security policy could probably allow for shared systems, according to Nigel Tozer, business development director at CommVault.
"From a management perspective, the regular spawning of new systems can mean they are accidentally missed from backup jobs or have their protection misaligned from their function," he said.
VM sprawl can also cause the virtual machine disk images to consume expensive primary storage capacity.
"When the virtual disks are set as dynamic, they grow based on the requirements, and when files are deleted within the virtual hard disk, this space is not returned to the available pool automatically," said Naveen Louis, director of tech support at Diskeeper Corporation Europe.
Kayleigh Bateman is the site editor for SearchVirtualDataCentre.co.uk.