It’s not Hyper-V — it’s the drivers!

March 12, 2010 in Virtualizationism by Eric Gray | 32 comments

VMware vSphere experts know that the ESX architecture has a critical advantage over other hypervisors like Xen, KVM, and Hyper-V.  Instead of relying on general-purpose third-party device drivers, VMware ESX comes with hardened, stress-tested drivers — ready for your toughest enterprise workloads.

Windows deserves applause for reliability improvements in recent years.  Unfortunately, the most reliable Windows design will never be able to counteract the damage that can be inflicted by a misbehaving device driver.  In fact, take a look at this slide from a Mark Russinovich TechEd session where he makes the point that the majority of Windows blue screens (BSODs) are caused by third-party drivers:

Experts agree — Windows reliability is a function of driver reliability.

What about those drivers included with Windows?

You might be under the impression that these third-party drivers are for off-brand NICs purchased from the clearance bin at Fry’s.  That’s not exactly the case — plenty of drivers are included right on the Windows DVD.

Consider this recent situation detailed by Mark Wilson.  He set up a Hyper-V test machine with some Intel PRO/100 NIC cards and when he plugged in an Ethernet cable — instant BSOD!

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Pimp My Hypervisor

March 1, 2010 in Virtualizationism by Eric Gray | 4 comments

I bet you never thought of Hyper-V as a tricked-out custom hypervisor — with one less layer than VMware ESX — but it is…

“Yo dawg, I heard you like Patch Tuesday, so I put Windows in your hypervisor so you can patch it while you virtualize!”

Inspired by a joke from Kendrick Coleman. With apologies to Xzibit.

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Taking snapshots of VMware ESX 4 running in a VM

February 26, 2010 in Virtualizationism by Eric Gray | 13 comments

Clearly, the capability introduced with VMware vSphere 4 that allows VMware ESX 4 to virtualize itself is a real crowd-pleaser.

However, one limitation that some have discovered while using this lab-testing technique is the lack of ability to use snapshots with virtual ESX systems.  In fact, after taking a snapshot of a virtual ESX VM, you will see the system boot into the recovery shell like so:

Ouch.

Can we fix it?

I asked some super-smart engineers inside VMware about the issue, and of course they know all about it and how to make it work.

The solution is to enable an undocumented advanced configuration option on the physical ESX host like so:

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Linux apps run directly on Windows with virtualization!

February 17, 2010 in Virtualizationism by Eric Gray | 20 comments

Microsoft has done remarkable things with virtualization — unbelievable, some say.

One outstanding achievement is the way the Hyper-V architects managed to completely collapse the guest operating system layer directly into the hypervisor.  Take a look at this diagram from a Microsoft Virtualization competitive brochure:

[Yes, it's that same brochure again.]

There are several key differences between Microsoft and VMware hypervisor architectures.  While the hardware and applications layers are pretty straightforward, applications don’t run directly on hardware.  As you are about to see, these two platforms take very different approaches when it comes to virtualizing workloads.

The VMware vSphere solution is to use a thin, high-performance virtualization layer that enables a single physical system to simultaneously host multiple virtual machines.  Each of these virtual machines executes isolated instances of traditional guest operating systems — Windows, Linux, Solaris, Netware, etc.

Due to apparent technological advancements in Hyper-V, it is now possible to run applications of all kinds directly on that integrated Windows OS/hypervisor layer without the need for a guest operating system at all.  This allows Microsoft to omit an entire layer from their virtualization architecture.

I’m sure you have seen various announcements about the exceptional support that Hyper-V has for Linux workloads.  Without a guest operating system layer, one must logically conclude that Linux applications are actually running on the Windows/Hyper-V hypervisor integration directly.  Spectacular!

I thought I’d test this technological breakthrough in the lab myself by running Postfix, a very popular Linux SMTP mail server, on Windows Server 2008 R2 with Hyper-V.  According to the diagram above, Postfix is classified as an application — the third layer. Read the rest of this entry »

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Hypervisor Footprint Quiz

February 10, 2010 in Virtualizationism by Eric Gray | 8 comments

Remember the hypervisor footprint debate?  You know, the one where Microsoft Virtualization declares that it is nothing but VMware FUD to tout the benefits of a small-footprint hypervisor.

I just found another point of view on hypervisor footprint size — take a look at this excerpt:

Small footprint: any features not applicable to our specific … scenarios are removed.  This guarantees that we do not have to worry about updating or fixing unnecessary code, meaning less churning or required reboots for the host.  All critical code paths are also highly optimized for our … scenarios.

Any guesses where that came from?  Must be more of that VMware FUD!

Actually, it was one of the Windows Azure design principles.  Which makes sense if you think about it — vSphere, with small-footprint ESXi,  is the perfect foundation for cloud computing.

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