Simon Crosby of Citrix Discusses Virtualization Heading into 2008

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 hi

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.

Q: When Microsoft announced Hyper-V, it was reported as if the clouds parted and the sun came shining through for the first time. Reports were made that this is VMware's biggest threat. Is that true?

Microsoft offers a scale of footprint that cannot be ignored. Over a period of time (say a year or two) a large section of the SME market will simply adopt the features provided to them with Windows Server 2008, including Hyper-V. Hyper-V is certainly not nearly as fully featured as Microsoft and the industry would have liked to see, however, XenServer, which leverages the Microsoft VHD format and is designed to extend the Microsoft user experience, offers a compelling, Microsoft compatible virtual infrastructure feature set to Microsoft customers today. Our customers are adopting XenServer as a virtual infrastructure platform that lets them move Windows and Linux VMs into production, sure in the knowledge that when Hyper-V offers the feature set to support that, those VMs can directly run in a Microsoft environment. Meanwhile, we will extend the Windows environment with high availability, disaster recovery, desktop delivery (VDI) and policy based automation solutions that add value to Hyper-V. It's worth noting that Hyper-V's ability to run Linux with high performance (enlightened I/O) is entirely dependent on the features that we deliver to Microsoft.

Is all this bad news for VMware? Yes.

Q: So if you had a crystal ball, do you think Xen and Microsoft will finally make VMware's ESX Server hypervisor pricing come down in the next year or two?

A: VMware is engaging in the art of marketing like never before. They are laying claim to management as the high ground for virtual infrastructure – and painting the vision of the next generation Datacenter OS. This is problematic in many ways. Our field tells us that VMware is heavily addicted to VI3 revenues, and is out attempting a land grab before we and Microsoft can gain significant share. They have artfully positioned VI3 as a combination of management and hypervisor, allowing them to state that the hypervisor is free, and they continue to load up on enterprise management features in VI3 Enterprise. This puts them in direct conflict not only with Microsoft and other OSVs at the platform layer, but also the established systems management vendors, who are increasingly alarmed at the idea of a powerful VMware selling data center management. Citrix is not a systems management vendor – we sell an affordable, powerful virtualization platform together with end-to-end application delivery automation solutions, partnering with Microsoft and with the major systems management vendors to make the offering directly interoperable with established ISV software and IT procedures. Another key category is Storage Management, where VMware appears to be going head to head with existing storage management, availability and clustering solutions, as well as changing the game on backup and image management. Our partnership with Symantec/Veritas allows us to deliver powerful VM-aware storage solutions without a forklift upgrade of the storage infrastructure.

Q: Often times I hear VMware speak about how Xen is an immature product. How do you respond to that?

A: The largest deployment of virtualization on the planet is built using Xen. Amazon, both internally and with EC2, leads the industry in terms of secure, massively scaled out virtualization deployments. Xen continues to beat VMware on performance, and it is being widely deployed by Google, Facebook and other major internet brands. I hope I don't need to point out that every virtualization offering on the market (including Hyper-V) draws from the Xen architecture – even the nascent feature set of KVM.

Citrix XenServer offers only (and all of) the core features customers need to get the key benefits of virtual infrastructure, in an open product that is extended by the world's leading innovators in different categories. Take fault tolerance for instance: Stratus and Marathon are both XenServer OEM partners. Marathon demonstrated five nines fault tolerant virtualization at VMworld – and won best new technology award – whereas VI3 is limited to VM restart. Our approach is to partner with the best in the industry, rather to try to re-invent or cut key partners out of the value chain.

Q: What's next for virtualization as a hypervisor and platform? Is it all about management down the road? Or are there other tricks of the trade that can be implemented?

A: 2008 is all about the hypervisor embedded in server hardware, and about the market getting real for VDI. XenServer will be an option on over 50% of x86 server hardware in 1H08, "baked in" during system assembly. This offers customers an incredible value proposition built into the box – and dramatically accelerates the adoption of virtualization. Citrix XenDesktop will launch in 08 too, and will be the industry's only comprehensive, end to end desktop delivery system, leveraging all of the key infrastructure components built by Citrix over the years for its core Presentation Server business today. Citrix believes that it can dramatically enhance the security and manageability of large scale desktop deployments, at a fraction of the cost and complexity of VMware's Propero-based first generation product.

Q: What are your customers telling you? Is there something specific that they are missing with Citrix and Xen?

A: Our customers love the product. They want us to deliver more features faster. Now that XenSource is part of Citrix you can expect to see us dramatically accelerate the rate of value-added features for XenServer, both based on our own development and our partner solutions that are certified as Citrix Ready. We believe we have everything that we need to compete head to head with VMware, and as the Citrix channel ramps on XenServer, we certainly hope to dramatically accelerate our own market penetration. Our business is still doubling quarter on quarter, which is very exciting.

Q: Do you see anything new or interesting in virtualization for 2008?

A: New features from the platform vendors include enhanced performance for enhanced page table support, our first support of I/O Memory Management Units (IOMMU) and virtual machine device queues that accelerate the I/O path for latency sensitive workloads. We aim to stay at the peak of performance and features through close collaboration with the hardware vendors. I see increasing interest in virtualization on client devices as well as VDI based virtualization of desktop OSes, to enhance manageability and security. Finally, I see a keen interest on the part of storage vendors to add value to their arrays and infrastructure to support virtualization functions natively. By way of example, XenServer today can directly invoke primitives on leading NAS Filers to initiate thin provisioning, snapshotting and cloning of VMs – something that is way beyond the reach of VMware with their proprietary cluster file system and legacy VMDK hard disk format.

Q: Server consolidation has been the battlecry for virtualization in 2006 and 2007, what's the next major use case to help push virtualization forward in 2008 with the remaining 95% of x86 servers?

A: In my view we have been too focused on server virtualization as the "hammer", which has to be applied to anything that looks like a "nail". We need to deliver the benefits of centralization, simplicity, dynamism, availability and automation for servers that aren't virtualized. Citrix Provisioning Server offers this today. It effectively performs a P2V of a native client or server image which it captures in a centralized storage repository. Servers and clients are set up to network boot, and their virtual hard disks are then streamed dynamically over the network. Provisioning Server scales massively – we can boot thousands of VMs from one Windows golden image, dramatically reducing the number of images to manage, and the complexity of OS patch and security management. The benefits: instant on provisioning of workloads, reduced patching, dramatically reduced storage needs, and an instantly scalable virtual or native data center environment.

Q: How has the Citrix/XenSource acquisition affected the Xen open source community? Can you tell us a little more about how this has played out?

A: As of Jan 1 the Xen project will have its first full time program manager focused solely on community development, and we will soon double the size of our open source development team – all courtesy of Citrix. The net effect will be an increased rate of development on Xen, from Itanium super computers to ARM based PDAs. The community has recently been strengthened with the addition of the multi-vendor Xen project advisory board, that oversees the project, recommends the roadmap and sets policies for licensing of the Xen trademark. The support that Citrix has given to the project is tremendous, and the most recent Xen developer summit was a strong demonstration of the strength of the project, with over 200 developers present. You can find the project at

Q: In your opinion, why is the open source approach to virtualization better than the approach VMware has taken? Are there any negative aspects to the open source approach?

1 2 Page 1
Page 1 of 2
How to choose a low-code development platform