I’ve been involved with virtualization for almost six years now, and I’m still learning new things about the technology -- and the community around it -- every day.
The major benefits of virtualization are well known to even the most novice users, but some of its gotchas and drawbacks only become apparent through years of experience. Here are some of the lessons I’ve learned during my years working with virtualization:
100% virtualization: Not always a good thing
Being 100% virtualized may give you bragging rights, but it’s not always practical. I learned this one the hard way during a data center power outage.
Leaving some core infrastructure components, such as DNS, DHCP and Active Directory, on physical servers can get you up and running more quickly in the event of a major problem. Virtual hosts are typically dependent on other infrastructure components, and if those components are not available, it can prevent your hosts from starting properly.
Being 96% virtualized is good enough. I like having the safety net of part of my critical infrastructure running on physical servers.
Help is out there
There is a lot to virtualization, and it is getting more and more complicated as it evolves. For those new to virtualization, it can be very intimidating to try and learn even the basics. Fortunately, there is no shortage of information to help you learn.
Hundreds of blogs are devoted to virtualization, and the Internet is full of other resources, from white papers to webinars to videos to podcasts. There are also many formal training courses -- online and in person -- that can quickly get you up to speed on the basics and dive deep into advanced topics.
Another good online resource is the VMware Technology Network (VMTN). I had a lot of questions when I was new to virtualization, and the VMTN forums had the answers for every one of them. No matter what your question is, there is a good chance that it has already been asked and answered in the forums. And if not, there are thousands of talented and experienced people who frequent the forums and can answer it for you.
Social media is a valuable tool as well. When many of my peers and friends were signing up for outlets such as Twitter, I kept resisting. Eventually I realized there is such a wealth of information available on social networks, and that to ignore it would be foolish.
Before social media, I would typically network with other people only once or twice a year, at VMworld and maybe another trade show. Twitter allows me to interact with thousands of people on a daily basis and stay current on what is happening in the industry. You don’t have to put a lot into it if you don’t want to, but at least get connected and start listening to what others are talking about.
Virtual infrastructure design is king
Once you understand the basics, you’ll find that using virtualization is easy -- in fact, too easy. You can download and install VMware ESXi and be ready to create virtual machines (VMs) in less than an hour. The problem is, there are many critical design decisions that need to be made before you create these VMs, to ensure that you have a healthy virtual infrastructure that will handle your workload demands.
When you start sharing resources among VMs, you need to ensure that these resources are balanced and that you do not experience any bottlenecks. Proper virtual infrastructure design must also take storage into account. Storage and virtualization are joined at the hip, as evidenced by the many storage companies that have closely tied themselves to virtualization -- none closer than EMC, which has held a majority stake in VMware since 2004.
Storage isn’t just a bunch of dumb hard drives anymore; a lot of features and intelligence have been added on both sides of the fence to make virtualization and storage very tightly integrated. You should design virtual infrastructures around a proper storage platform that serves as the foundation for all the VMs running on hosts. You need to get it right up front, or you will pay the price later on.
In recognition of the importance of virtual infrastructure design, VMware created two certifications, the VMware Certified Advanced Professional-Data Center Design and the VMware Certified Design Expert. Take the time to develop a strong virtual infrastructure design, so you can experience the benefits of virtualization without all the headaches.
Traditional methods don’t work well in virtual environments
When you virtualize, you’re not in Kansas anymore. Everything is different, and you need to change your mindset. The methods and tools that you use to manage physical server infrastructures don’t always work well in virtual infrastructures. You need to throw out what you learned managing physical servers and start over. If you don’t use tools and methods specifically designed for virtual infrastructures, you will end up struggling.
Virtualization can make you an outsider
IT professionals who are involved with virtualization love it, but those who don’t may resist it. Change is difficult for many people, and virtualization is a big change that affects everyone in the IT department. Rather than forcing the technology onto those who resist it, help them understand what virtualization is all about and how it works. If you spend the time to demonstrate the many benefits that virtualization provides, they’ll warm up to it.