中英对照：WindowsServer虚拟技术前瞻

http://www.winsupersite.com/showcase/viridian_preview.asp
声明：此文版权属于原作者Paul Thurrott，在转载此中文翻译时，请注明来自中文业界资讯站cnBeta.com。译者LonelyJames。

Microsoft this week shipped the Release Candidate 0 (RC0, and no I don't understand the naming convention either) version of Windows Server 2008, allowing customers to get their hands on near-final code of the upcoming OS for the first time. Windows Server 2008 RC0 doesn't differ much from a functional perspective from the previous release, a June 2007 Community Technical Preview (CTP) release (see my Windows Server 2008: Need to Know showcase for more information). But it does come with one major new feature: The first public pre-release version of Windows Server Virtualization (WSV), codenamed Viridian.

本周微软发布了Windows Server 2008 的 RC0版本（我也不知道命名规则）（译者注：有点像腾讯哦），第一次允许用户接近即将到来的操作系统的快要完工的代码。2008 RC0与上一个发行版，也就是2007年6月的CTP（社区技术预览版）相比，在功能展望这方面区别不是很大。但是他带来了一个主要的全新功能：这是研发代号为Viridian的Windows Server 虚拟技术（WSV，Windows Server Virtualization ）的初次亮相。

A look at Microsoft's virtualization technologies
展望微软的虚拟化技术

If you're not familiar with Viridian, it's helpful to understand where Microsoft's virtualization solutions stand today. Currently, Microsoft offers a free server product called Virtual Server (and an accompanying free desktop product, Virtual PC) that provide traditional (i.e. user mode) virtualization environments. Virtual Server could very well be the pinnacle of this type of technology, at least from Microsoft, given that it will be obsolete as soon as the more performant, maintainable, and efficient WSV arrives next year. For those looking ahead to this future, Virtual Server's Virtual Hard Drive- (VHD-) based virtual machines will work fine--if not quite a bit better-if and when you later upgrade to Windows 2008 with WSV.

假如你不熟悉Viridian，了解一下微软现在提供的的虚拟化解决方案会对你有所帮助。现在，微软提供一个免费的服务器产品，名叫 Virtual Server（下简称VS） （附带一个免费的桌面产品，Virtual
PC），他们提供一个传统的虚拟化环境（比如用户模式）。在这类技术方面，VS很轻易地占据了顶尖位置，不过至少从微软的角度来说，等到明年更高性能、更易管理、更有效率的WSV新鲜出炉的时候，VS就会变成明日黄花。对于想要向前看的人们，假如从现有环境升级到带有WSV的Windows Server 2008，VS之中基于虚拟硬盘驱动器（VHD）的虚拟机还会照常工作——没准还会表现得更好一点。

On the management side, Microsoft offers Virtual Machine Manager, an enterprise-class virtual machine management solution that's currently aimed at Virtual Server customers but will be updated for WSV once that technology becomes available. VMM extends the basic capabilities of Virtual Server management, which is generally designed for managing the virtual machines on a single physical server, into a more scalable solution. VMM offers centralized virtual machine management across hundreds or thousands of physical machines, and can handle thousands, or even hundreds of thousands of virtual machines.

在管理方面，微软提供虚拟机管理器（Virtual Machine Manager），这是一个企业级别的虚拟机管理解决方案，面向VS使用者，而当技术条件成熟，就会被更新到WSV里面。VMM对虚拟服务器管理系统的基本能力进行了扩展，上述系统为了在一个单独的物理服务器上管理虚拟机而设计，而VMM将更进一步。VMM提供对多个——成百上千个——物理服务器的虚拟机集中管理的能力，这样他就可以控制数以千计，乃至数以百万计的虚拟机。

VMM automates many crucial tasks. For example, virtual machines that are running out of resources on one physical machine can be automatically relocated to new hardware with minimal disruption and end user transparency. VMM also provides for physical to virtual (P2V) conversions, as well as virtual to virtual (V2V) conversions of VMware virtual machines to Microsoft virtual machines. (And say what you will, but that last feature should prove quite popular.)

VMM让许多重要的工作自动完成。比如，在一台物理机器上运行的虚拟机，假如出现了资源溢出的情况，就会被重新定位到另一台拥有空闲资源的，且对最终用户透明的机器上去。VMM还提供物理机到虚拟机的转换（P2V），以及从VMWare虚拟机到VPC虚拟机的转换，也就是虚拟机到虚拟机（V2V）。（不管你会怎么想，我看后一项功能会大受欢迎。）

Unlike Virtual Server (and the upcoming WSV), VMM is not free, but given its expansive feature set this is somewhat unsurprising. You can get into VMM as cheaply as $499 for a version that can manage up to 5 physical host servers. Beyond that, you're in volume licensing territory.

VMM是要收钱的，尽管VS和即将到来的WSV依然不收钱；不过看这些晃眼的功能，收点钱也就不足为怪了。5台物理机器的VMM许可证收499美刀，再多的话就要走批量许可了。

Enter Viridian
走近Viridian

This week, I'm excited to finally be able to provide more detail about Windows Server Virtualization, as this is a technology that we've all been waiting to get some hands-on time with. Here's what I know so far.

本周我很高兴能向大家提供关于WSV的更多信息，毕竟这是一项我们等待已久的实用技术。下面就是现在我所知道的：

Bryon Surace, a program manager in Microsoft's Virtualization team told me in a briefing earlier this month that the overall schedule for WSV hasn't changed. The company still intends to ship a beta version of WSV when Windows Server 2008 is completed in the first quarter of 2008. What they've shipped this week is a pre-beta, or alpha, version of the technology that is essentially feature-complete. It is not, however, extensively tested, so you shouldn't expect to use WSV anywhere near production servers. Even the branding for WSV is still in play: While Microsoft might use the WSV name for the final version of the product, it is considering other options.

一位微软虚拟技术团队的项目管理者Bryon Surace本月早些时候简要地告诉我WSV的发行计划不会改变。在2008第一季度到来的时候，Windows Server 2008也将准时完工，那时候WSV的一个Beta就会同时放出。但是，这个版本不会经过广泛的测试，所以暂时不要指望随着服务器一睹WSV的芳容。现在就连WSV的命名也成了问题：对于最终版本的产品，微软可能会使用WSV作为商品名，也可能会用其他名字。

"The big issue here is that Viridian is a component of Windows Server 2008 and not a separate product like Virtual Server," Surace told me. "It's a brand new architecture based on the Windows Hypervisor. From a management perspective, Viridian is installed and managed as a role under Windows 2008, just like DHCP, file and print services, and so on."

"重要的是Vidirian是 Windows Server 2008 的一个组件，而不是像VS那样的独立产品。"Surace跟我说，"这是基于Windows Hypervisor的一个全新的工程。从管理远景来说，Vidirian在Windows 2008下安装并扮演一个角色，就像DHCP，文件与打印服务什么的。"

Contrary to some reports, WSV can be installed on either a Server Core install of Windows 2008 or a more traditional install of the product. That said, Microsoft strongly recommends that any future live deployments of the technology should occur on Server Core, because that type of near-bare-metal install type will provide a smaller attack surface and better performance. So while the company will support WSV installs on traditional Windows 2008 servers, it is essentially providing that option mostly for testing purposes.

与某些报告正相反，WSV既可以在Win2008的服务器内核环境安装，也可以像传统软件一样（译者注：通过安装程序）安装。

Another issue to consider is the underlying hardware. Though Windows 2008 will ship in both 32-bit (x86) and 64-bit (x64) variants (as well as some versions for the Itanium platform), WSV will be available only on x64 versions of the product. (And while the specific product versions haven't yet been locked down, Surace tells me that WSV will be an option on all x64 versions of Windows 2008, and not limited to certain versions.) The reason for this limitation is that WSV relies on hardware virtualization features that are only available in the latest AMD and Intel chipsets.

下一个要关心的问题是下层硬件（the underlying hardware）。尽管Win2008将会同时推出32位和64位版本（正如为安腾平台开发的某些版本），WSV只会在64位平台生效。（而且在特定产品版本还没有被锁定的情况下，Surace告诉我WSV会成为所有64位版本Win2008的一个可选组件，不限于某一特定版本。）这一限制的原因是某些虚拟机功能只能由AMD或Intel的最新芯片组来支持。

WSV will support both 32-bit and 64-bit guest operating systems, which in WSV parlance run in child partitions. (The host OS runs in the so-called parent partition.) It will support up to 32 GB of RAM in each guest OS, a huge improvement over the 3.6 GB limit in Virtual Server 2005. WSV will also support allocating up to 4 physical CPU cores to each guest OS.

在客体系统（译者注：Guest OS，也即虚拟机使用的系统）方面，WSV支持32和64位系统，它们将被安排到不同的子分区。（主机系统运行的分区相应地被称为主分区。）每个客体系统至多支持32G内存，与Virtual Server 2005里面3.5G的限制相比简直是巨大的飞跃。WSV支持每个客体系统使用4核的物理CPU。

Aside from the underlying architectural differences, the big difference between WSV and Virtual Server, and indeed, other virtual machine platforms like those provided by VMWare, is that WSV supports the notion of virtualized, or synthesized, devices. In other systems, the hardware that's "seen" by each guest OS is emulated, which makes for decent compatibility but poor performance, Surace said. WSV's synthetic device drivers improve performance by dramatically reducing the number of traversals the system needs to make between kernel mode and user mode.

把这些潜在的架构上的不同抛在一边，WSV和VS——事实上还包括VMWare等其他虚拟机平台——之间的大差异表现在，WSV引入了虚拟"设备"（Devices）或者合成"设备"的概念。Surace如是说，在其他系统中，客体系统"看到"的硬件是模拟出来的，这使得它们兼容性极好，但是性能差的可以。WSV的合成设备驱动通过戏剧性的削减系统在内核模式与用户模式之间切换所需要的遍历（traversals）来提高设备的性能。

"This is a new approach that removes the performance bottleneck," Surace told me. "We call it OS enlightenment: The OS knows it is using synthesized device drivers and knows that it's being virtualized. It's similar to the para-virtualization scheme in Xen [an open source virtualization engine]." Enlightened OSes include Windows Server 2003 and 2008, and Microsoft is partnering with Xensource to ship drivers for Linux so that Linux, too, can be "enlightened."

"这是又一项除去性能瓶颈的举措，"Surace告诉我。"我们管这个叫做'OS教化（OS enlightenment）'：系统明白它使用的是合成的设备，知道这是虚拟出来的。这和Xen〔一个开源虚拟引擎〕中的'并行虚拟'（para-virtualization scheme）相类似。"Windows Server2003和2008都属于被"开光"的系统，微软正与 Xensource
合作以传输驱动程序到Linux，从而使Linux也"开光"。

敬请期待本文下半部份