Everything is Beautiful
I recently attended a conference where virtualization was the hot topic. One CTO even boasted about how many physical servers he had retired - it was impressive. But, when I asked him what his effective throughput rate or transaction rate was with the new virtual environment as opposed to his physical server infrastructure he gave me a very blank look. It is not an uncommon occurrence - many top IT professionals don't look at their metrics before they do something, and then have no idea how they have helped, or hurt, themselves.
The obvious positives of virtualization are clear - lower power consumption, simpler server duplication/replication, easier server management, simpler IP address and VLAN management, etc. The Aberdeen Group conducted a study in 2008 which outlines some of these issues. In it they found that organizations experienced 18 percent reductions in infrastructure cost and 15 percent savings in utility cost by virtualizing their server environments.
But, there are times when other performance measures need to be considered. There is a quantitative aspect to everything - that is a given, but there is also a qualitative aspect to most things - and that is often more important.
Honey, I shrunk the server!
So - this CTO took his server environment from 180+ servers to fewer than 60. What did he virtualize? In his own words, "everything." And he did, I followed up with him and they have virtualized everything, but after our meeting at the conference he began to think more on what we had discussed about performance and throughput. Since he had no metrics prior to virtualizing he had to use a more ad hoc method - user feedback. This is often problematic unless you have vetted the responses objectively.
To his chagrin he noticed that trouble tickets related to his BES (blackberry enterprise server) had risen by 25% in the 30 days since that environment was virtualized. A huge rise given his company has more than 1300 Blackberry users. If only his people had done their homework ahead of time they would have realized, based on other companies experiences, that BES can be virtualized, but there can be some sever IO penalties and performance can (and most often does) suffer.
To P2V or not to P2V : that is the question?
E-Commerce systems were some of the first to be virtualized because of their, typically, web based components. Web servers, typically, do very well in a virtualized environment. Some will argue that virtualization was made for web servers and internet application servers. But is this a global truth? There is a great deal of evidence that virtualization can muddy the waters when it comes to performance.
The Aberdeen Group's June 2008 report shows that organizations can experience up to a 9 percent loss of overall revenue if issues exist with business-critical application performance. Seventy Four percent of the organizations surveyed also reported problems with application performance which coincided with a significant drop in customer satisfaction.
A key challenge for organizations adopting virtualization is effectively managing application performance in virtualized environments. The capabilities required in a virtual environmetn were not necessary when these organizations were looking to achieve the same performance goals in physical environments.
So, it isn't just technological hurdles that need to be overcome, it is also mindest and personnel factors that need to be upgraded when making the move from P2V (Physical to Virtual).
Full Speed Ahead...
One of the biggest uses of virtualization is server consolidation. Many larger companies had, for the longest time, multiple data centers that interacted and interfaced continually (or using batch processing). Users in each location logged onto their local servers which then exchanged data between sister servers in other locations. WAN traffic was, thus, consolidated and data greatly compressed.
With virtualization, many companies have opted for more centralized computing environments. So, users in Europe now have to log onto servers in the US, whereas before they logged onto servers locally. WAN traffic then starts to increase and system bottlenecks become more common. These are not abstract observations or "what-if's." They are real life occurrences that companies have experienced. Because of the increased WAN traffic, the end user experience, for internal and external users, was not improved and actually degraded.
Thus the moral to this story - PROPER PRIOR PLANNING PREVENTS POTENTIALLY POOR PERFORMANCE. Your choice, when dealing with bandwidth issues, becomes larger pipe or better use of it. For many companies, the gains they see in virtualization can be quickly wiped out by the need for larger internet or network bandwidth. Thankfully, for many, WAN accelerators can be put in place, but it is always better for this to be considered as part of the initial virtualization plan instead of being an afterthought.
Recap
Here are only a few factors to consider when making the move from Physical to Virtual environments:
- Obtain performance metrics for as many aspects of your physical environment as possible so you can actually see what has improved and what has not as a result of virtualization.
- Identify, in advance, what technologies are not suited to being virtualized.
- Consider what you are consolidating and look at bandwidth as a factor - you can recover from poor planning, but you only get one chance to make a good first impression.
- The WAN is often more sensitive than the LAN - look at what impact virtualization will have on your Wide Area Network.
- Ensure that visibility into your entire transaction flow is not lost by moving from a physical to a virtual environment. This is one of the areas where individual server statistics can be obscured in a virtualized environment.
- Measure the quality of your end user experience before you start a virtualization project.
- Identify ways of managing your Service Level Agreements around applications hosted in a virtual environment.
- Anticipate performance issues in the planning stages of your P2V project. The more you think of ahead of time the better the overall experience will be for all involved.
Also published on THE CTO FORUM
