Choosing to virtualize your control systems
As we review our current facility control systems status we contemplate whether virtualizing part of or all of our control server/workstation environment is possible. With the looming concern of the retirement of Windows XP and the discontinued support from Microsoft after April 2014, virtualization of those legacy workstations will allow a more controlled migration to new operating systems and software platforms.
I’ve seen an uptick in requests from customers on whether to virtualize or continue with a physical server environment in their new control systems. A lot of the drive behind the customer’s request is the increased interaction with the customer’s IT organizations and their control system organizations. IT organizations have embraced virtualized environments and have deployed them for many years in the business environment. One note of caution is to not approach a virtualized environment from a business environment perspective and apply it to your control system. The reason being business systems typically do not have a 24/7 high-availability requirement, which is common for all manufacturing and process control systems.
So when you start to build a virtual environment with either VMware or Microsoft’s Hyper-V you can reduce the number of physical servers and still provide redundancy and high-availability with backup. For example, when you implement HMI/Data Server/Historian/Domain Controller server redundancy that could require eight physical servers, which you can reduce to three virtual servers (primary, secondary, and a third virtual server to provide backups) using the native software redundancy included in those products. That’s not to say that all of the servers could not be hosted on one powerful virtual server, but having three virtual servers removes the single point of failure in your virtual control system environment.
One of the trade-offs with virtualizing your control system is that you will need support from your IT organization, which is in short supply, or you will need to invest in training of your control system engineers so they may support the plan of a virtualized control system environment. Virtualizing some workstations, such as Windows XP, for obvious reasons will solve some of the problems with the obsolescence of that operating system, and allow you to continue to use applications that require Windows XP that does not mean that those applications are necessarily compatible with a virtualization. There may be no choice but to run an application on Windows XP in a virtual environment even though it is not officially supported by the vendor. I highly recommend that you do your homework and check with your control system software to make sure that they support virtualized environments. The last thing you want is to get on a support call with your software vendor and to find out that they don’t officially support virtualized environments and they cannot help you.
My last piece of advice is: Don’t go it alone, seek out a great integration partner with deep multiple vendor experience in virtualized control systems.
This post was written by John Boyd. John is the Technology Leader at MAVERICK Technologies, a leading automation solutions provider offering industrial automation, strategic manufacturing, and enterprise integration services for the process industries. MAVERICK delivers expertise and consulting in a wide variety of areas including industrial automation controls, distributed control systems, manufacturing execution systems, operational strategy, business process optimization and more.