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Author Archives: Mark Chuang

About Mark Chuang

Mark currently leads product marketing for VMware's storage, disaster recovery, and database solutions. In his time at VMware, he has focused on solving customer's biggest IT challenges.

Microsoft Acts Quickly on License Reform – but only when it is in the Best Interest of the Customer… and Microsoft

The CALs Licensing Saga from Last Month

About a month ago, we blogged about a burdensome expense Microsoft imposed on its customers running a non Windows Server 2008 VM on Hyper-V. Excerpt from our blog:

Here’s the scenario: Say someone’s got existing Windows Server 2003 licenses (non-OEM versions) and CALs. He wants to use these licenses and CALs to run a Windows Server 2003 virtual machine. Seems pretty straight forward – as a 2003 CAL is being used to access a Windows Server 2003 environment – and a good way to save money since he’s already paid for the Windows Server 2003 licenses and CALs – right?

[Microsoft licensing doc] seems to say is that, if I want this Windows Server 2003 virtual machine to run on the Hyper-V version that comes with one of the Windows Server 2008 editions, then I must upgrade all of my Windows Server 2003 CALs to Windows Server 2008 CALs. List price for a Windows Server 2008 Client CAL works out to be about $40 a CAL.

Note: An astute reader pointed out that this issue applied not just to Windows Server 2003 VMs, but also to Linux VMs running on Hyper-V – basically to any non Windows Server 2008 VM.

Well Done Microsoft on Making a Customer-friendly Change

Well, last week, less than a month after our post, Microsoft changed this customer-unfriendly CALs policy. IDC also reported on this change – click here to read IDC’s summary (requires a free IDC account registration).

Here’s the key update straight from Microsoft’s documentation: Microsoft Volume Licensing Brief “Licensing Windows Server 2008 to Run with Virtualization Technologies, January 2009” – Page 7 (highlights added):


This is good news for Microsoft customers (and proof that customers can influence Microsoft policies)! Why should they have to pay for Windows Server 2008 CALs when their application is running in a Windows Server 2003 VM and the customer already paid for Windows Server 2003 CALs? Or why should they buy Windows Server 2008 CALs for a Linux web server running on Hyper-V? From this regard, we applaud this move by Microsoft because it does the right thing for the customer.

But There’s Much More to Be Done

But we do continue to see another disturbing trend… (you knew this was coming), namely that Microsoft is quick to make changes when the change benefits Microsoft, but it seems to delay addressing its licensing and support policies that obstruct a organization’s full use of virtualization solutions when a change to that policy doesn’t help Microsoft’s own cause.

IDC sums this up nicely in its own brief – click here to read (requires a free IDC account registration)

Of course, [Microsoft] is more motivated to flex its policies when it benefits Microsoft products as much as, or more than, competitive products, which is increasingly the case as Microsoft’s presence in the virtualization software space continues to ramp up.

You see, Microsoft had to make the change to its CALs policy to remove a Hyper-V disadvantage compared to other virtualization vendors like VMware, Citrix, Novell, etc. On all of these other platforms, a customer could take an existing (paid for) Windows Server 2003 license and CAL and run it on VMware / Citrix / Novell / others without having to pay for a new Windows Server 2008 CAL. If Microsoft had not made this change, Hyper-V would have been left at a distinct cost disadvantage to every other virtualization platform.

But on other customer unfriendly licensing issues, like linking all operating system licenses to the physical server, Microsoft has been slow to act even though customers continue to ask for it – see Chris Wolf’s recent blog on how his clients (especially service providers) continue to ask for this. Based on feedback from VMware customers running Windows applications, here are three Microsoft licensing and support changes that would greatly help customers get the full benefits of virtualization:

  • Provide customers an option for all Microsoft OS and application licenses to be assigned to the virtual instance (instead of physical hosts) so customers can take full advantage of VM mobility.
  • Allow third parties (ex. ISVs) to have an ability to distribute demo and production VMDK-based Windows virtual appliances so customers can deploy them in their virtual datacenters.
  • Lift restrictions in VECD where customers must pay a significant premium for virtualized desktops in exchange for “expanded license grants” that they do not necessarily need (or want). Currently, VECD works for a limited number of sophisticated customers, but makes the use of Microsoft products in virtual desktops very expensive for customers seeking simple, uniform deployment of consistent desktop environments.

We’ll continue to work with Microsoft on these issues, but it also helps when Microsoft hears directly from you. Microsoft’s change in application licensing to allow greater benefit in a virtual environment was a direct result of customers providing direct feedback to Microsoft – it does work! Please write in and comment on licensing and/or support issue that you’d like to see Microsoft improve – at least within the context of virtualization. Let’s continue this dialog with Microsoft – tell them what you’d like to see happen.

Do I really need to upgrade all my Windows Server 2003 CALs in order to run on Windows Hyper-V?

A partner brought something to my attention recently that seemed odd regarding Microsoft licensing – and potentially expensive.

Here’s the scenario: Say someone’s got existing Windows Server 2003 licenses (non-OEM versions) and CALs. He wants to use these licenses and CALs to run a Windows Server 2003 virtual machine. Seems pretty straight forward – as a 2003 CAL is being used to access a Windows Server 2003 environment – and a good way to save money since he’s already paid for the Windows Server 2003 licenses and CALs – right?

But here’s where it gets weird. On page 11 of the Microsoft Windows Server 2008 Licensing Guide (download Microsoft doc here) is the following paragraph:


To Virtualize Win2003 on Hyper-V, I Need to Buy Win2008 CALS…a Hidden Expense

What the paragraph seems to say is that, if I want this Windows Server 2003 virtual machine to run on the Hyper-V version that comes with one of the Windows Server 2008 editions, then I must upgrade all of my Windows Server 2003 CALs to Windows Server 2008 CALs. List price for a Windows Server 2008 Client CAL works out to be about $40 a CAL.

Wow, if I’m reading this correctly, that’s a lot of extra cost to deploy Windows Server 2003 virtual machines on Hyper-V!

It Was Validated By a Third Party

To try to verify this, I did some searching on the Internet and turned up this report update from Directions on Microsoft, an independent 3rd party analyst firm covering all things Microsoft. The update is specifically about Microsoft’s free, standalone product Hyper-V Server 2008, but one section provided good clarification on this CALs issue.

“Unlike the regular Windows Server 2008 editions that include Hyper-V, Hyper-V Server does not automatically trigger the need for clients who access VMs to have Windows Server 2008 Client Access Licenses (CALs).”

Interesting… so Microsoft Hyper-V Server 2008 doesn’t require you to upgrade to Windows Server 2008 CALs to run Windows Server 2003 VMs, but the Hyper-V that comes with Windows Server 2008 editions does. This seems to confirm that there is significant additional cost to deploy Windows Server 2003 licenses on Hyper-V.

I Don’t Need the Win2008 CALs If I Use the “Standalone” Hyper-V Server, But Then I Don’t Get Any Functionality Either

This licensing policy seems to encourage people who want to use their existing legacy Windows licenses to run it on Hyper-V Server 2008. But even Microsoft’s own website says that “Hyper-V Server 2008 only offers the most basic of virtualization features,” and it has significant limitations that prevent anyone serious about deploying virtualization from using it.

  • No high availability support (i.e., no Microsoft Cluster Services support)
  • No host memory/RAM support over 32 GB
  • No host CPU support over 4 processors
  • No local graphical user interface

To get any of the above, one would need to use the full instance of Hyper-V with Windows Server 2008 – it would require a full re-install of Windows Server 2008 on the host (after paying for a Windows Server 2008 license), a time-consuming process that results in virtual machine downtime.

Of Course, VMware Solutions Are a Better Option

There’s a much better choice: run your Windows Server 2003 / 2000 VMs on VMware ESX. You could use your existing Windows Server 2003 / 2000 CALs (which you’ve already paid for – no need to upgrade to 2008 CALs), and you don’t face any of the functionality limitations of Hyper-V Server 2008. You could even deploy on VMware’s free ESXi product and do a license key upgrade (no re-install required) when you decide to take advantage of the advanced functionality in one of VMware’s pay products. Of course, these licensing advantages are in addition to all the other reasons why VMware is a better choice – see the “Why Choose VMware” website.

Am I reading this Windows Server 2008 CALs requirement right? Have you run into this CALs requirement in your deployments?

At Virtualization Event, Microsoft Says “Get Virtual Now”… but Wait Until 2010 for Live Migration

Walking out of the keynote at Microsoft’s “Get Virtual Now” event in Bellevue, WA this week, I found myself thinking about how this was the second time that Microsoft has pre-announced that they would have live migration for Hyper-V. (Apparently, I was not the only one — see “Microsoft Backtracks on Live Migration, Again” on internetnews.com.)

For any readers new to virtualization, live migration is the ability to move a running virtual machine (VM) from one physical server to another without the VM end-user experiencing any disruptions. This capability enables IT admins to do things like:

  • Perform planned maintenance at anytime (instead of only during evenings, weekends, or maintenance windows),
  • Perform anytime dynamic load balancing to meet real-time application demands, and
  • Save power by consolidating VMs to fewer servers during non-peak hours.

VMware was the first to deliver live migration in 2003 when we released VMware VMotion. Since then, others have followed VMware’s lead and delivered live migration (such as various Xen-variants in 2007). According to our customers, live migration via VMotion has become an indispensable component of their virtualized production datacenters.


Microsoft Live Migration: Take One

The first time Microsoft pre-announced live migration for Hyper-V was in 2006 when they stated that “Viridian” (codename for Hyper-V back then) would ship with live migration and other capabilities that would surpass VMware ESX. Then in May 2007, Microsoft had to retreat and drop live migration, hot-add memory and CPU, and support for 32 logical cores from Hyper-V 1.0 in order to prevent Hyper-V from slipping further. (Remember, these dropped capabilities were the ones that Microsoft previously touted as reasons Hyper-V would surpass VMware ESX.)


Microsoft Live Migration: Take Two

So now we get the second pre-announcement on live migration which says that live migration will be available in Windows Server 2008 R2. According to what Microsoft had previously told press, R2 is slated for 2010. Onstage Bob Muglia stated something to the effect of “there’s no magic in live migration, it is just a feature…” Well if it is as easy as the statement implies, why doesn’t Microsoft have the functionality now? Why will it take until 2010?

Now you may say, “Yes, Microsoft is late, but I’m ok waiting.” But waiting costs your company real dollars. Look at this simple example: By using VMware VMotion for planned server maintenance in a 150-VM environment you can save almost $60,000 a year in operational costs. If we scaled to a 1000-VM environment, it results in almost $400,000 of cost savings a year. If you use VMotion for more than planned server maintenance, and use it for dynamic load balancing, distributed power management, etc, you’ll save even more!

live migration cost savings


Live Migration is a Core Virtualization Requirement

To pre-announce live migration – twice – shows that even Microsoft has realized the foundational role that live migration plays in a virtual datacenter. It’s not a “nice-to-have” but a “must-have” capability. Microsoft used to claim that Microsoft Quick Migration was “good enough” because it only caused seconds to minutes of downtime – but that downtime causes interruptions to the end user and that is unacceptable. Microsoft must have gotten enough grief from customers over this claim because I don’t see them saying it as much any more. Anyone who has actually used VMware VMotion knows that you can’t afford the downtime — look at this demonstration of how disruptive the downtime caused by Microsoft Quick Migration is to an end-user.

Assuming no further slips, when Microsoft delivers live migration in 2010, it will be seven years behind VMware (VMotion in 2003). Today, VMware has distinct advantages over Microsoft in our VMware Infrastructure 3 product, such as Storage VMotion, logical resource pools, DRS, and in our Application and Management Infrastructure products, like VMware Lab Manager, Stage Manager, Site Recovery Manager, Lifecycle Manager. By 2010, VMware will extend our leadership even further – keep an eye on announcements coming at VMworld 2008.


Microsoft Did Demo Live Migration, but…

As a technical aside: Microsoft’s live migration demo during Bob Muglia’s keynote felt kinda weird (see for yourself – available in .mpg or .wmv) with what seemed like a streaming video player super-imposed on top of the Cluster Administrator console. During the actual migration, the video was stretched to full screen, obscuring the Cluster Administrator console, and then shrunk back down once the migration was declared as completed. I realize the video was supposed to show that the live migration did not disrupt the playing video, but it wasn’t very convincing since streaming video can be cached. Not sure Microsoft cares what I think, but I have some suggestions to make it a more compelling demo:

  • Show an RDP session into the virtual machine being migrated so people can see what happens to someone logged into the virtual machine
  • Show a continuous “ping” to the virtual machine being migrated so people can see any downtime of that virtual machine
  • Show the management console during the entire migration so people can see what the admin will see
  • Show a more complete process of how to initiate a virtual machine live migration, ie. select target host, test for compatibility, etc.

Here’s an example of how we’ve demoed VMotion.

Yankee Group rescinds own report, but Microsoft continues to distribute it…

VMware met with Yankee Group to provide our feedback on the factual inaccuracies in the report "Virtualization Price War: VMware’s Little Big Horn?". We did this around the same time we put up our blog posting summarizing the issues point-by-point. Yankee Group understood our concerns, agreed to do a revision to address the issues, and promptly took down the original report from its website several weeks ago.

Because of the factual inaccuracies in the report, Yankee Group also committed to requesting that Microsoft, who had purchased distribution rights to the report, cease distributing the original report. However, three weeks after our discussion with Yankee Group and three weeks after Yankee Group pulled the report from its website, Microsoft still continues distributing the report, such as in the Microsoft Virtualization Newsletter that just went out on 4/2/2008.

I wonder why Microsoft would continue distributing a report as marketing material, when the author, Yankee Group has rescinded the report…

Those Darn Details… Issues in Yankee Group’s Virtualization Report

Yankee Group recently came out with a report “Virtualization Price War: VMware’s Little Big Horn?” that unfortunately contained quite a few factual errors, inaccuracies, and unsupported claims. The report was not reviewed with VMware prior to publication (as some have claimed). Therefore, VMware is listing the factual errors and inaccuracies in the report because they distort the true cost and value of VMware’s solution. Happy reading.

1. Exhibit 2: Double counting, omissions, and other issues

Exhibit 2 indiscriminately mixes VMware’s bundle and ala carte pricing, making it very difficult for readers to get an actual apples-to-apples cost comparison. If the table is meant to be a cumulative account of Microsoft and VMware pricing (i.e. add up all the rows), then there is significant double-counting in the VMware column. If the rows in the table are meant to be interpreted individually, then there are gross inconsistencies between how VMware and Microsoft’s costs are shown. Most casual readers will assume the table represents cumulative cost for both companies since they see the word “Included” throughout Microsoft’s column. The points below are written from the cumulative cost standpoint.

  1. Double counting on cost of VMware: Row 1 of Exhibit 2 calls out the list price for VMware Infrastructure 3 Enterprise Edition ($5750) in the VMware column. However, the table continues by calling out the ala carte pricing for VMware individual capabilities that are ALREADY included in the price of VI3 Enterprise Edition (i.e. VMotion, DRS, HA, vSMP). This table effectively double-counts the cost for VMware. VMware offers ala carte pricing for customers who wish to purchase one of VMware’s other editions and add features individually. No one would buy Enterprise Edition plus many of the ala carte options in Exhibit 2 because most are included in the Enterprise Edition. There is a reference to a Mr. David Dodge on page 9 of the report that points out this issue but the feedback was apparently ignored.
  2. Double counting on OS costs for VMware: The cost of a Windows Server Enterprise Edition License is counted twice for VMware – once under “Guest Licensing” and again under “Windows Server”. In this configuration, VMware products only require 1 Windows license (just like Microsoft), not 2. Again, Mr. David Dodge calls this out on page 9 of the report – “Dodge also argued that the VMware ESX3 solution can install on bare-metal and does not need an operating system to boot.” Therefore, the “Windows Server” for VMware should be $0 (the cost under “Guest Licensing” already covers it).
  3. Wrong VMware product for a “single server configuration” comparison: The top of page 7 states that Exhibit 2 is a comparison of cost for a “single server configuration.” If that is the case, then why wasn’t VMware Server (further discussion in section 2 below) or the VMware Infrastructure Foundation Acceleration Kit used? The analyst is clearly aware of the acceleration kit because it is cited on page 6 of the report. Such bundles from VMware are specifically targeted at this segment. Also, if this is a single server configuration, when why would a customer want VMotion, DRS, HA which is only useful in a multi-server configuration?
  4. Lack of clarity on management costs: Exhibit 2 fails to point out that a Microsoft System Center Enterprise Management Suite License (ESML) is $860 PER managed HOST (not including the mandatory cost of 2-years of Microsoft SA) while a VMware VirtualCenter Management Server license is a perpetual license independent of the number of managed hosts (VirtualCenter agents come with the VI3 license). By purchasing 1 VirtualCenter Management Server license, a customer can manage 5, 10, 15, 200, etc. number of ESX hosts. Also, where is meant by “Additional Charge $3,750 for Standard” (in the Management row)?
  5. Error – Microsoft Virtual Server does NOT support vSMP: Microsoft Virtual Server does not support virtual SMP. That’s one of the key differentiators that Microsoft calls out between Virtual Server and Hyper-V.
  6. Microsoft features not on-par with VMware features: Microsoft Virtual Server + SCVMM R1 offers nothing like DRS. SCVMM R1 can only recommend a physical server for initial placement when a VM is first provisioned. It has NO ability to dynamically move the VM (based on customer defined resource requirements) within a cluster of hosts to maximize resources. Also, Microsoft’s self-service provisioning is much less capable compared to VMware Lab Manager. For instance, Lab Manager handles self provisioning and management of multi-tier environments. SCVMM R1 offers nothing comparable.
  7. Omission of key features in VMware VI3 Enterprise Edition: The report does not call out many capabilities that customers get if they purchase VI3 Enterprise Edition today. If the report is going to compare VI3 Enterprise Edition to Microsoft Virtual Server, then it should show all of the core capabilities of Enterprise Edition to provide readers an accurate picture of what they are getting. Omitted VI3 Enterprise Edition features include:
    • Storage VMotion (no MS equivalent)
    • Update Manager (no MS equivalent)
    • Guided Consolidation (no MS equivalent)
    • 64-bit guest OS support (no support in MS Virtual Server)

2. Why wasn’t VMware Server compared to Microsoft Virtual Server?

On page 7, the report states the following for why VMware Server was not used in this comparison.

"Customers do have the option of deploying VMware’s free hypervisor technology to even out the cost differential between VMware and competing server operating system-based hypervisors. However, according to the Yankee Group 2006 and 2007 Global Virtualization Surveys, which polled 800 end users worldwide, only 10% of corporations are deploying the free version of VMware for production networks." (Page 7)

This rationale is a double standard – what percentage of Microsoft Virtual Server deployments are currently in “production networks?” VMware’s internal research and anecdotal evidence suggests that MS Virtual Servers’s use in product environments is low. Certainly, it is not as high as the >85% of VMware customer deploying VI3 in production. At a bare minimum, a VMware Server vs. Microsoft Virtual Server comparison should have been included for comprehensiveness sake (since this is supposed to be an “unbias” report showing readers various cost options).

Also, comparing a Type 2 hypervisor (virtualization layer running on top of a host operating system), like Microsoft Virtual Server, with a Type 1 hypervisor (hypervisor running directly on top of the hardware), like VMware ESX Server, is a flawed comparison. Microsoft’s own plan to move away from Virtual Server and replace it with Hyper-V is evidence of the gap in the products. They know that a Type 2 hypervisor is architecturally dependent on the host operating system which impacts its performance and scalability. For instance, Microsoft’s customer references for Virtual Server (see Microsoft slides from TechEd 2007 as an example) consistently show a 3:1 to 5:1 consolidation ratio. On the other hand, many of VMware’s public customer references for ESX Server (see www.vmware.com/customer) achieve 10:1 and even >20:1 consolidation ratios.

3. Inaccurate reporting in the Security section

Inaccurate reporting of security bulletin: The two sentences below, as written, are misleading. The vulnerability to break out of the guest system to the host machine is only an issue on VMware’s hosted products (ex. Workstation, VMware Server). The Yankee Group report misleads readers to believe that the vulnerability affects VMware ESX Server.

"In late September, the online security alert service Bugtraq reported that VMware issued fixes to patch 20 security vulnerabilities that affected almost every product in its portfolio, including the VMware ESX Server, the VMware Server, VMware Workstation, VMware ACE and VMware Player. These vulnerabilities could have allowed hackers to break out of the guest system in the virtual machine and to halt processes on host machines." (Page 12)

Another inaccuracy in reporting: The report makes another inaccurate claim about a recent security bulletin (see quote below). First, the 20 security flaws in sentence 1 apply to both VMware hosted and ESX products. Of the 20, 5 applied to VMware’s hosted products. Therefore, the 18 attributed to ESX Server in sentence 2 is wrong. Second, only 3 (out of the 15 flaws that are applicable to VMware’s datacenter product ESX Server) were rated as high severity or critical. The majority of the others are low criticality. This fact would have been readily apparent by clicking through to view the details of the Secunia report. (Secunia summary bulletins only show the worst threat level among all the patches.)

"VMware released a patch to correct more than 20 security flaws in its various products. According to an alert issued by Secunia, a Denmark-based security service provider that tracks security flaws in software and operating systems, 18 were described as highly critical flaws that could impact just about every version of the ESX Server." (Page 12, emphasis added)

Apples-to-oranges: Comparing a hosted to a bare-metal product: Comparing vulnerabilities in Microsoft Virtual Server 2005, which is a hosted product, to all of ESX, which is a bare-metal (hypervisor) product, is a totally apples-to-oranges. If Yankee Group wants to compare to Microsoft’s hosted product, then it should compare bugs to VMware Workstation or VMware Server. If Yankee Group is going to compare a hosted product in the datacenter to a bare-metal product, it should include all the vulnerabilities in the computing stack. For Microsoft Virtual Server 2005, it needs to run on Windows Server 2003 and uses IIS. So how many critical Windows Server 2003/IIS vulnerabilities have there been since Jan 2007?

4. Other inaccuracies and unsupported claims

Have Citrix XenServer list prices really gone down?

"And in response to the increasing competition, Citrix in January announced new pricing for its offerings that represent a 20% cut." (Page 12)

As best as we’ve been able to track, it appears that Citrix XenServer list prices have actually gone up slightly, not down. At best, they’ve stayed about the same. Here’s our understanding of how Citrix XenServer list prices have changed.

Prices below are for two-socket hosts.

Old price New price
XenServer Ent Ed Perpetual 2499 2600
XenServer Ent Ed SnS 500 400
XenServer Ent Ed Annual Sub 1599 2000
XenServer Std Ed Perpetual 750 780
XenServer Std Ed SnS N/A 120
XenServer Std Ed Annual Sub 495 600


Confusion between Microsoft Virtual Server and Hyper-V

"Microsoft leveraged its greater economies of scale by embedding Virtual Server into the Windows operating system free of charge." (Page 7)

Microsoft Virtual Server R2 SP1 is not embedded into the Windows operating system. It requires a separate download and installation. This quote confused the architectures of Microsoft Virtual Server and the upcoming Microsoft Hyper-V.


Does this pricing comparison with Red Hat make sense?

"[Red Hat] retail price tags are 35% to 70% less than the same competing products from VMware." (Page 13)

Red Hat is sold only on a subscription basis and VI3 is sold in perpetual per-socket licenses, so a comparison like this is invalid unless the users plan to expire the machines in 12 months.


Who really has broader hardware support…

"’We’re way ahead of VMware in our support for I/O virtualization, native 64-bit HA as well as the total number of CPUs supported and we support a much broader set of hardware,’ Crosby claimed." (Page 16, emphasis added)

A check of VMware’s HCL and Citrix XenServer’s HCL shows that Simon Crosby’s claim about broader hardware support is unsupported. For example, VMware 3.0.2 HCL supports over 400 server platforms. XenServer’s HCL only shows 43 servers directly tested by Citrix. Even if the server systems tested by vendors are added, the Citrix HCL grows to 55 servers. Mr. Crosby’s other 2 claims about I/O virtualization and 64-bit HA are pretty unsubstantiated as well.


Out-of-date information on VMware VI3 capabilities

"The Infrastructure Enterprise software also includes some new features… DRS… HA… VCB." (Page 15)

VMware has had DRS, HA, and VCB since June 2006. On the other hand, nowhere does the report mention the truly new features of VI3 (version 3.5) that were announced in Sept 2007 and GA’ed in Dec 2007. Readers are not getting current information from this report.


VMware VirtualCenter has had intelligent placement since VI3 in June 2006.

"He added that the functionality in VMware’s corresponding virtualization management offering falls far short of the functionality in Virtual Machine Manager. ‘VMware’s Lab Manager development tool focuses on desktops, not servers and even their new Virtual Data Center tool does not incorporate the intelligent placement feature of the Microsoft product,’ he said." (Page 11, emphasis added)

VMware VirtualCenter has had intelligent placement capabilities (for when a new VM is provisioned) since June 2006 with the launch of Virtual Infrastructure 3.

Corrections to ZDNet blog ‘Microsoft’s Hyper-V puts VMware and Linux on Notice’

ZDNet posted a blog reviewing Microsoft Hyper-V beta “Review: Microsoft’s Hyper-V puts VMWare and Linux on notice” (February 14, 2008). The posting had some factual errors and other claims about VMware ESX Server – see below for a summary. The author of the blog has acknowledged the errors in the comments section of the blog but since most readers won’t read through all the comments, here is a summary of the correct statements about VMware ESX Server as well as counterpoints to various claims.

Claim: VMware ESX Server does not support SATA disks.

"… SATA disk drives, which are now commonplace on commodity x86 server machines, are not currently supported in VMWare ESX 3."

Correction: VMware ESX Server 3.5 supports SATA disks. The author has acknowledged this in the comments section.

Claim: VMware ESX Server always requires VMFS and a dedicated SAN-based LUN to store virtual machine images.

“ESX Server also requires a special networked clustered file system known as VMFS to store the virtual machine images, and you have to dedicate a SAN-based LUN to it.”

Correction: ESX Server provides four options for VM storage: 1) Fiber channel (FC) attached, 2) iSCSI attached, 3) NFS, and 4) local storage. Only the FC and iSCSI options require a SAN-based LUN. Also, the NFS option does not use VMFS. Again, the author has acknowledged this error in the comments section. Note that Citrix XenServer and Microsoft Hyper-V also require shared storage to perform VM migration and other high availability functions.

Claim: VMware is a closed system. Therefore, VMware development goes at a much slower pace. VMware’s lack of SATA disk support is an example of this slower pace.

“VMWare keeps its ESX hypervisor source code very close to the vest, so development goes at a much slower pace – SATA disk drives, which are now commonplace on commodity x86 server machines, are not currently supported in VMWare ESX 3.”

Counterpoint: VMware’s purported lack of SATA disk support has already been refuted (see above). In addition, VMware has delivered more industry-breaking innovations around x86 virtualization compared to anyone else. As examples, VMware was the first to deliver virtual SMP, live migration (VMotion), centralized VM management (VC), dynamic load balancing (DRS), automatic VM restart after host failure (HA), next-generation thin embedded hypervisor (ESX Server 3i with a 32MB disk footprint), and Storage VMotion. The majority of other vendors still have not delivered these capabilities. VMware has also provided ESX Server source code to partners as part of the VMware Community Source Program. One good example of the output from the Community Source Program is the Mellanox Infiniband support.

Claim: VMware ESX Server’s hardware compatibility list (HCL) severely limits a customer’s hardware choices while Microsoft and Xen do not have this issue.

"However, [ESX Server] has a much tighter environment as to what kind of hardware it can run on – the hypervisor has a limited device driver compatibility list…"

Counterpoint: Both Microsoft Hyper-V beta and Xen-based products (ex. Citrix XenServer, Virtual Iron) have HCLs as well. Click here to see Microsoft’s list of hardware platforms “suitable” for Hyper-V beta. Click here to see Citrix XenServer’s HCL. Click here to see Virtual Iron’s HCL. The Microsoft, XenServer, and Virtual Iron HCLs are actually more limited than VMware’s HCL. For instance, Microsoft has directly tested Hyper-V beta on 8 servers (TBD what the hardware requirements will be for Hyper-V GA). Citrix has directly tested 45 servers. Virtual Iron has directly certified 29 servers (for version 4). In contrast, VMware has over 400 servers on the ESX Server 3.0.2 HCL. Click here to see VMware’s HCL.

Claim: VMware ESX Server is “pure software based virtualization”

"VMWare’s ESX differs from Hyper-V and Xen in that it currently uses pure software based virtualization…”

Counterpoint: This statement can potentially mislead readers to think that ESX Server is based on software emulation technology. This conclusion would be false. For the bulk of x86 CPU instructions, ESX Server does direct execution on the physical CPU. Readers may also interpret this statement to say that VMware is somehow philosophically opposed to using CPU hardware-assist. Again, this would be a false conclusion. VMware takes a pragmatic approach and uses whichever technology delivers the best performance. Currently VMware binary translation has advantages over today’s generation of CPU hardware-assist. Click here to read a VMware whitepaper on this topic. In regards to the future, VMware is already working closely with Intel and AMD on their next-generation of CPU hardware-assist technology.