In a homogeneous VMware ESX cluster, all CPU instructions in the underlying host CPU are exposed to guest operating systems.  VMware vCenter Server also offers the state-of-the-art Enhanced VMotion Compatibility (EVC), allowing administrators to specify a baseline in a mixed cluster that maximizes use of most modern CPU features during transition to newer generation hardware.

VMware ESX 4 CPU Features

CPU-Z is a handy utility that displays comprehensive technical information about a CPU.  Here it is running on a VMware ESX VM powered by an Intel Xeon E5540 “Gainestown” processor — a Nehalem-class CPU with most of  the latest instructions, such as SSE4.1 and SSE4.2:

Virtual machines running on VMware ESX are able to take advantage of those features that are designed to improve application performance — giving you your money’s worth after investing in new hardware.

Now let’s take a look at an alternative approach…

RHEV Hypervisor: Pentium II Inside!

You probably know by now that Red Hat has abandoned Xen in favor of the more modern KVM.  So how did the architects behind Red Hat Enterprise Virtualization (RHEV) deal with CPU compatibility across KVM hosts?

They decided not to expose the true underlying CPU details and advanced instruction sets.  Instead, they take a more conservative approach and masquerade as an old Pentium II Celeron CPU — no pesky SSE4 instructions to deal with here:

That’s the virtual CPU presented to guests even in a cluster of identical Nehalem hosts!  This is as “good as it gets” for RHEV.

Now, to be fair to KVM — the open source project on which RHEV is based — the capability to expose all physical CPU features is present, it’s just that Red Hat has not designed a suitable management feature such as VMware EVC to take advantage of it.

Red Hat claims that RHEV is just like vSphere, but cheaper (where have we heard that before?).  Is it?

The Hypervisor is not a Commodity

Are you buying new hardware for your virtualization project, paying a premium for hardware with the latest performance capabilities?  Keep in mind that not all hypervisors are created equally.  Only VMware has EVC — and that’s just one of the many reasons why vSphere is the best platform for your Red Hat Enterprise Linux and Microsoft Windows Server workloads.  Why build virtual silos in your datacenter with OS-centric hypervisors rife with compromises?

Get the best, most mature virtualization: VMware vSphere.

Related posts:

1. What is Red Hat Enterprise Virtualization?
2. Red Hat Enterprise Linux is not Enterprise Virtualization
3. Red Hat Enterprise Virtualization HA [ha ha]
4. Dear Red Hat…

The author worked extra hard to refute all 9 points — but I do admit being somewhat distracted by the gratuitous use of VMWare throughout.  Evidently, proofreading — unlike immeasurable technology and services discounts — is not one of the benefits extended to guest posters these days, which is a shame.

The Microsoft Virtualization MVP tries to use most of the pages from the playbook, such as memory overcommit FUD:

Relying on a host to overcommit memory to support failover hosts is potentially dangerous and incorrect oversubscription leads to all VMs suffering from performance.

Have you ever had a VM suffer from performance?  I have, and believe me — it’s not pleasant.

But here is a familiar line:

… I would never over commit my VM hosts in production.

Where have we heard that before?   I almost forgot to mention that this guest poster is none other than Chris Steffen — the star of that now-infamous CIO Magazine article who once called VMotion a “gimmick” and said:

I don’t know what kind of environment other than QA or development, or in a staging environment you’d want to do [live migration], but it’s not going to be in any production environment I’m responsible for; it’s not going to be any environment dependent on any kind of SLA or performance requirements. The justification for the inherent risk just isn’t there.

But what does Mr. Steffen say now that Hyper-V has Live Migration?  About what you’d expect — and more:

Also keep in mind that using the System Center suite, the Microsoft solution can Live Migrate VMs to other hosts due to situations that VMware servers cannot even monitor, such as CPU Power, Power Supply Failures, and Fibre Channel congestion.

There are a number of other gems in this convincing piece.  Did you know:

• Hyper-V is more stable than and at least as secure as VMWare [sic]
• vSphere is just as new as Hyper-V

Yep, there is a full-day supply of Kool-Aid in that guest post.

Nice work, Microsoft Virtualization team.  I’m not so sure this sort of thing helps your cause — please keep it up.

Related posts:

1. The Truth About Hyper-V Memory Overcommit
2. On Quick Storage Migration in R2
3. Hello Dynamic Memory?
4. How to see if Quick Migration is right for your workload

You can think of the VM console like a remote KVM for virtual machines  — similar to HP iLO on a physical machine.  Most of the time there are more efficient network-based remote access techniques like RDP or SSH.  However, there are some circumstances — like network misconfiguration — that absolutely require the use of a remote console.

Have you ever wondered what would happen if you were connected to a VM console while it automatically migrated with VMotion to another physical host?  If you are a long-time VMware admin, you would probably expect things to keep on working.  And that is exactly right — the console connection is seamlessly transferred to the new VMware ESX host.  This behavior is especially important when VMware DRS is dynamically moving virtual machines to optimize cluster resources.

Need to check the network settings of a VM?  No problem — you may not even notice if that VM migrates to another host while you are connected.

Here is a quick video of the situation in action:

Does Microsoft Hyper-V and System Center Virtual Machine Manager 2008 handle this scenario the same way?  Not exactly.

Related posts:

1. Hyper-V Console Disconnects During Live Migration
2. VMotion from physical ESX 4 to virtual ESX 4
3. Dear Red Hat…
4. Awesome performance through VMware DRS

Today I’d like to point out an article from ZDNet that continues the tradition with the upcoming Quick Storage Migration feature in R2:

Unlike VMWare’s storage migration feature, Storage vMotion, Microsoft has chosen not to use a “Live” storage migration approach with their Quick Storage Migration, which suspends VM activity for several minutes while the VMs are being moved, after which the VMs are resumed from suspend. Microsoft insists that this is to ensure referential integrity of the data being moved, and that the majority of large enterprise customers which they worked with to integrate this feature did not do storage migration during production hours.

Unbelievable.  Interesting use of the word “chosen.”

I’ll be sure to link back to this blog post when Hyper-V 2013 comes out and Microsoft finally has Live Storage Migration.  Stay tuned!

But seriously — are you using Storage VMotion to move production virtual machines?

Related posts:

1. How to see if Quick Migration is right for your workload
2. Hyper-V More Stable, Just as Mature as VMware vSphere?
3. Exclusive: Hyper-V 2013 Product Roadmap
4. Hey boss, where do you want these virtual machines?

Both the physical and virtual ESX systems are connected to a shared iSCSI LUN.

Related posts:

1. SCVMM Damage Control
2. VMware ESX 4 can even virtualize itself
3. Hello Dynamic Memory?
4. vSphere Console Stays Connected During VMotion

Brace yourself for a tidal wave of FUD from Redmond that perhaps only the Linux community has known.  Here are a couple examples for you.

Take a look at this item from the Top Ten Benefits list:

Support for Microsoft Virtual Server and VMware ESX
With this release, VMM now manages VMware ESX virtualized infrastructure in conjunction with the Virtual Center product. Now administrators running multiple virtualization platforms can rely on one tool to manage virtually everything. With its compatibility with VMware VI3 (through Virtual Center), VMM now supports features such as VMotion and can also provide VMM-specific features like Intelligent Placement to VMware servers.

Wow, isn’t this amazing.  Now even VMware users can benefit from the awesome and innovative Intelligent Placement.  At last!  The only problem with this statement is complete omission of the fact that VMware DRS has had an intelligent placement option since its release over two years ago.  You may recognize it:

Here is another little gem from the FAQ:

Q. Does this product enable “live” migration or zero downtime migration of workloads across physical servers?

A. Yes, when used with the VMware’s Virtual Center product, VMM can move workloads across physical hosts via VMotion. In a Hyper-V environment there is a short service interruption as workloads are moved via Quick Migration. The length of that service interruption will depend on the time needed to copy the files from one source server to the target, and will be sensitive to storage and network infrastructure. The migration wizard will automatically detect SAN infrastructure and will enable the admin to choose to migrate files over SAN at much faster pace.

Emphasis mine.  VMM hasn’t enabled anything, it is calling a VMware API.  They neglected to mention the fact that VMware ESX is also required.

How is that any different from this:

Q. Can you haul this sofa in your Volkswagen Beetle?

A. Yes, I will borrow my friend’s truck to haul the sofa.  I can also haul two of the cushions in my VW.

Note to Microsoft: VirtualCenter is one word, not two.

Related posts:

1. May I speak to the manager?
2. On Quick Storage Migration in R2
3. SCVMM Damage Control
4. SCVMM 2008 Management Pack Finally Released

A typical, albeit incorrect, comparison goes something like this:

• Both products are bare metal hypervisors
• VMware has lots of great features, like VMotion (live migration)
• But those great features make the solution more expensive
• Hyper-V (with quick migration) is good enough

The other day a colleague pointed out a Microsoft blog that upped the ante one further, taking this quote from an iTNews article:

“You’ve got to question whether it’s worth paying $50,000 for that. I know the VMware camp go on about features like VMotion, but for $50,000 I could pay someone to move my virtual machines for me.”

Several commenters on the article have already questioned the legitimacy of this $50K figure; I’ve got nothing to add there.  You can deploy a VMware solution for less than that.

The part that really strikes me is the misguided concept of paying someone to move VMs.  It’s really not clear how any amount of additional money/personnel in your organization could help you move VMs without downtime in a Hyper-V environment.

So now, be on the lookout for another critical talking point to appear in future VMware vs. Microsoft articles:

• Money saved by not buying VMware can be used to hire additional system administrators

“Hey boss, where do you want these virtual machines?”

Related posts:

1. How to see if Quick Migration is right for your workload
2. On Quick Storage Migration in R2
3. Exclusive: Hyper-V 2013 Product Roadmap
4. What would things be like without VMFS?

So, the best thing to do is to test the applications that will eventually run in virtual servers with Quick Migration and see what happens. Then, in a physical server with the installed application, run it and use it to perform an action. Mid-way through the process, disconnect the network cable, count to 10, restore it, and see what happens.

Is Quick Migration “good enough” for your workload?  Don’t count on it.

Related posts:

1. On Quick Storage Migration in R2
2. Exclusive: Hyper-V 2013 Product Roadmap
3. Hey boss, where do you want these virtual machines?
4. Hyper-V Console Disconnects During Live Migration