Simon Crosby, former CTO of XenSource and now CTO of the Virtualization and Management Division at Citrix Systems, is well known in the industry as a virtualization and open source champion.

As we leave 2007 behind us and push forward into 2008, I wanted to find out where Citrix stood in this growing virtualization environment. Between the incredible news about the Citrix acquisition of XenSource and then the high energy and excitement that took place during Citrix iForum, who better to speak with than Simon Crosby to find out more about Citrix, virtualization and what's coming down the road in 2008 - a year where virtualization really starts to attack the remaining 95% of x86 servers that refused to drink the kool-aid in 2007.

Virtualization Report: With all the buzz and constant chatter about the benefits of virtualization, how do you answer people when they ask about the downsides? Do you think there are any?

Simon Crosby: There are downsides to poorly planned virtualization deployments. Before anyone begins a virtualization project, it is important to know what the end goal is, and exactly what they are trying to achieve. Simply buying an expensive virtual infrastructure product because it's all the buzz is certain to not deliver the benefits you want, unless you have a clear view of the intended outcome. So I always say "Start at the end – ask yourself what benefits you want to have achieved." If you simply want to reduce server count, power use, save rack space and upgrade your server infrastructure, our entirely free XenServer Express Edition or XenServer Standard Edition may be enough. Indeed we have over 150,000 users of these affordable production-grade server consolidation products today – from Police department 911 services, to very large enterprises. If you're looking to virtualize your infrastructure wholesale, then the objectives include greater flexibility, dynamism, security and availability – things you can't achieve by carrying on the way you are. These features are offered in our powerful, yet affordable Enterprise Edition product, which offers all you'll need to manage a virtualized server, network and storage infrastructure as a pool of resources. Few projects end in total failure – but the cool factor can wear off fast if you've paid a lot for your virtual infrastructure and you suddenly find that you also need to change out your backup procedures and storage management tools. It all takes planning. Customers that think ahead tend to have more successful outcomes. Many of those use Citrix XenServer.

Q: AMD and Intel are now focused on virtualization and adding support for it at the chip level, what does that mean for Citrix?

A: Hardware assisted virtualization is the most important trend in x86. We rely entirely on this innovative feature to give us great performance that follows the standard hardware "shrink and clock up" curve. Thus far we are seeing over 300% performance increase year on year for hardware accelerated virtualization, something that a purely software based solution such as VMware's cannot take advantage of. Moreover there is a very exciting pipeline for additional hardware support – Extended Page Table support, I/O virtualization are two that spring to mind. The net-net is that we see the overhead of virtualization rapidly reducing to insignificant levels – we recently demonstrated 9.6 Gb/s iSCSI block I/O to and from guest VMs on XenServer, using a Solarflare NIC card, for example.

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Read the rest of my InfoWorld Q&A session with Simon Crosby, here.