VMware vSphere still trounces the competition.  Paul Venezia, who drove this multi-vendor effort, considered many aspects of virtualization technology and concluded:

VMware still has advanced capabilities that the others lack. VMware also offers a level of consistency and polish that the other solutions don’t yet match. The rough edges and quirks in Citrix, Microsoft, and Red Hat aren’t showstoppers, but they demonstrate that these alternatives all have hidden costs to go along with their (potentially) lower price tags.

Here is the scorecard, summarizing the various categories tested:

Congratulations to the incredible team behind VMware vSphere – the original and still the best!

Related posts:

1. Disingenuous Cost Comparisons
2. What is Red Hat Enterprise Virtualization?
3. Multiple hypervisors? What about multiple SANs?
4. Citrix Not Focused on Server Virtualization?

Welcome Discussion

The virtualization community certainly responded to the various RHEV articles, and it was great to hear from some new voices as well as the usual suspects in the interesting discussions that ensued.  One new commentator in particular, using a pseudonym, provided valuable technical affirmation based on obvious stick-time with RHEV.

Unfortunately, some of the commentators did not disclose their affiliation.  I was particularly disappointed to see Red Hat employees — or people connecting from Red Hat IP address space — commenting without disclosure.

Several opposition voices lost sight of the fact that RHEV is not merely a synonym for open source virtualization, nor is it even equivalent to Red Hat Enterprise Linux running the KVM hypervisor.  The discussion did go off on a few other tangents, but overall the conversation remained civil.

Correcting the Record

The RHEV website has been recently toned down, featuring not-quite-as-misleading marketing buzzwords and no longer making the bold claim that RHEV is “best in class” as seen in this screenshot of the previous version:

Red Hat even removed the “Competition” page entirely, throwing a 404 error now instead.  Whether or not those corrections were a result of this article series is open to debate.

But wait… there’s more

Franky, I have a whole queue of topics left to cover — but the opportunity cost is too high to spend any more effort correcting the range of misleading RHEV claims.  Perhaps I will revisit this series with the release of RHEV 3 or RHEV 4 if the accompanying rhetoric warrants it.

Don’t forget to check out the RHEV summary page for a quick overview of the whole series.

Thanks for reading.

Related posts:

1. RHEV Manager — It’s not just a clever name
2. What is Red Hat Enterprise Virtualization?
3. Best of 2010
4. Idle RHEV Hypervisors save power?

RHEV Comparison Whitepaper

Red Hat published a PDF comparing RHEV to VMware vSphere and Hyper-V.  Here is one of the entries on virtual storage:

Okay, so far so good.  Apparently, as with vSphere, virtual disks are simply files and can be stored on any of the various storage domains.  If you missed the last post on how RHEV Data Centers are limited to a single storage technology, please be sure to check it out — it’s not like vSphere.

As it turns out, the fact checkers were off the day Red Hat released that handy comparison whitepaper.  Because if you actually went through the effort to set up RHEV and create virtual machines, you would never find anything resembling a virtual disk file on the host.

Logical Volume Manager

RHEV virtual disks are actually stored in cryptically named logical volumes – no encapsulation or portability here.

Did you spot the file?  While it is common to say that “everything in UNIX is a file” this is taking that old adage to an extreme, wouldn’t you say?  Storing virtual disks in this fashion makes it nearly impossible to move VMs between hosts – even if they are powered off.  And you can forget about easily storing archive or DR copies of important VMs in an alternate location.

Even if you are running Red Hat Enteprise Linux virtual machines, the best and easiest virtualization platform to deploy, configure, and manage is VMware vSphere.  Try for yourself and see.

Related posts:

1. Multiple hypervisors? What about multiple SANs?
2. RHEV Manager — It’s not just a clever name
3. Red Hat Enterprise Virtualization HA [ha ha]
4. What is Red Hat Enterprise Virtualization?

As you may recall, Red Hat is attempting to bring their new RHEV product to market by playing the old “don’t get stuck with a single vendor” trick.  Red Hat’s CEO claims:

“…customers don’t want one platform. They want two.”

Let’s save the multi-hypervisor discussion for another day, but shift to the topic of storage diversity.

While there may be a few environments that can standardize on a single storage area network technology, it typically  makes sense to mix and match iSCSI, NFS, or Fibre Channel SANs to optimize for cost and performance.

During my recent foray into the chaotic world of Red Hat Enterprise Virtualization, I encountered an unbelievable storage limitation with their new KVM hypervisor.

“Virtualization diversity… when and where we say”

VMware vSphere customers are free to mix and match supported storage technologies within datacenters, clusters, and even hosts.

I would have thought that a company like Red Hat that is pushing heterogeneous solutions and multiple vendors might feel the same way when it comes to storage.  But that’s not quite how things go in the land of Red Hat Enterprise Virtualization.

With RHEV, a “Data Center” is configured to use a single type of storage;  all clusters and hosts in that Data Center are restricted to that, so choose wisely:

Storage Freedom

VMware vSphere allows administrators to move virtual disks for running VMs from one array to another — even between different types of arrays — with zero downtime.  Storage vMotion is a very powerful feature and it is simply not available from Red Hat – only VMware.

The Best Choice: VMware vSphere

Virtual machines have differing storage requirements — certainly not a one-size-fits-all component of an efficient virtual infrastructure.  The best platform for building your own private cloud is also the one with the broadest support for today’s storage technologies:  VMware vSphere.

Oh, by the way, did you know that VMware is positioned in the Leaders Quadrant of Gartner’s newly-released x86 Server Virtualization Magic Quadrant.  Take a look at the full article — I’ll give a free subscription to the VCritical RSS feed to the first 10 people that spot Red Hat’s position.

Related posts:

1. What is Red Hat Enterprise Virtualization?
2. These are not the files you are looking for
3. Red Hat Enterprise Linux is not Enterprise Virtualization
4. RHEV Manager — It’s not just a clever name

Q: How much power does an idle server consume?

A: Way more than a powered-off server.

VMware vSphere saves energy — and money — in your datacenter by powering off unused hosts during off-peak periods.  Take a look at this new technical paper on VMware DPM that covers the technology in-depth.

Despite competitor claims, this powerful capability is unique to VMware vSphere.

Imitation: The highest form of flattery

Red Hat Enterprise Virtualization has a seemingly-similar feature called Power Saver that also consolidates virtual machines onto fewer hosts.  However, the RHEV solution stops there — hypervisor hosts simply sit idle with no running VMs; they are not powered off.  No word yet on what the moon and stars in this diagram have to do with an idle host:

Red Hat claims that an idle host requires just 10-15% of the power required for a host with running VMs.  That sounds very generous if you ask me.  Frankly, from the looks of my HP C7000 BladeSystem Onboard Administrator power summaries, it seems quite false.

Update: Bob Plankers actually measured the power consumption of a Dell server in a few different scenarios and found that idle systems still draw significant amps.

Red Hat claims their new virtualization product is “best in class.”  Really?  Which class?

Related posts:

1. Multiple hypervisors? What about multiple SANs?
2. Red Hat Enterprise Virtualization HA [ha ha]
3. RHEV Manager — It’s not just a clever name
4. RHEV Wrap-Up

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…

What happens when the other major component of a RHEV infrastructure fails?  Can you rely on RHEV High Availability (HA) to quickly and reliably restart affected VMs when a RHEV Hypervisor fails? It depends – as you will see.

First, let’s make sure everyone is up to speed on HA capabilities provided by the gold standard in virtualization:

VMware HA

VMware HA is a robust feature that was first introduced with Virtual Infrastructure 3 in 2006.

VMware vCenter Server is required to configure HA options and add VMware ESX hosts to a cluster, but after that vCenter is hands-off — ESX hosts communicate among themselves to reliably restart virtual machines.  In fact, VMware HA can even restart vCenter Server if it is running inside a protected VM — wrap your head around that one.

Powerful options are available for administrators, such as specifying the restart priority of virtual machines and whether or not to force VMs to power off if a host becomes isolated from the rest of the cluster.

VMware has heavily invested in this technology, reducing risk  for customers that virtualize with vSphere.  For even more information on VMware HA, take a look at Duncan Epping’s HA Deep Dive.

RHEV HA [ha ha]

Looking at this Red Hat Enterprise Virtualization competitive comparison, you’d might assume that RHEV and vSphere are on equal footing when it comes to protecting virtual machines with HA:

Unsightly details behind the marketing

RHEV HA sounds great in the marketing brochure, but there are a few problems with the execution.  RHEV Manager is a single point of failure — running on a physical Windows box — and it’s also the actual brain behind HA.  Yes, RHEV-M is responsible for restarting virtual machines when a host fails.  If the manager is down, no HA for you!

That alone makes RHEV HA something less than “HA” for most production environments, but there are a few other key weaknesses:

• HA must be manually enabled for each virtual machine — no cluster-wide settings
• No cluster admission control — administrators must manually ensure sufficient capacity would be available in a cluster to accommodate a host failure
• No VM restart priority to ensure the most critical workloads and dependencies are brought online first
• Primitive split-brain protection requires IPMI or other out-of-band management interface to force a host shutdown
• Cannot protect the RHEV Manager itself — chicken-and-egg situation

Wow, I didn’t notice those details in the comparison brochure.

Decide

Whether your datacenter is running Windows Server or the mighty Red Hat Enterprise Linux, doesn’t it makes sense to trust the proven leader in virtualization?  VMware vSphere is simply the most reliable platform for consolidating workloads and building your private cloud.  Going beyond exceptional HA is VMware FT – mirroring mission-critical VMs on backup hosts means zero downtime from host failures.

Related posts:

1. Red Hat Enterprise Linux is not Enterprise Virtualization
2. What is Red Hat Enterprise Virtualization?
3. Red Hat Enterprise Virtualization: Pentium II Inside!
4. RHEV Manager — It’s not just a clever name

Red Hat makes some strong claims about RHEV worth scrutinizing:

Compared to the competition feature by feature, Red Hat Enterprise Virtualization offers best-in-class, cutting-edge enterprise virtualization features.

In this article, we’ll take a more detailed look at the RHEV Manager.

It’s The Manager

Make no mistake about it, RHEV-M is not just a manager, it is The Manager for Red Hat Enterprise Virtualization.  There are no other interfaces for administrators to create, start, stop, or migrate virtual machines.  No command-line utilities and no option for a management client to connect directly to hypervisor hosts.

They could have called it…

Red Hat Enterprise Single-Point-of-Failure

RHEV-M is one seriously mission critical component of the RHEV infrastructure, so it is surprising to see that there are no high-availability options for RHEV-M — no clustering or other redundancy support.

Even the approach of protecting RHEV-M by deploying it in an HA VM is also impossible — something that works just fine for vCenter Server and even System Center VMM.  That’s because RHEV-M is the sole management tool for RHEV, creating a chicken-and-egg situation that essentially mandates the use of a physical system.

Red Hat is asking their loyal Linux customer base to deploy a physical Windows box — that is a single point of failure — to manage their open source hypervisor.  I did not notice that bullet point on their competitive comparison document.

In fact, Red Hat goes so far as to say:

… today, server virtualization is not used pervasively in the production enterprise datacenter. Some of the barriers preventing wide-spread adoption of existing proprietary virtualization solutions are performance, scalability, security, cost, and ecosystem challenges.

It never occurred to me that VMware, the aforementioned proprietary virtualization solution, had so many challenges.  How does vSphere management measure up to RHEV Manager…

VMware vSphere: For all Mission Critical Workloads

While VMware vSphere also has a Windows-based manager — vCenter Server — it is not a single point of failure. The vSphere Client performs equally well when connected directly to a VMware ESX system to perform necessary management or configuration and various command-line utilities and scripts can be used without vCenter Server.  Also note that VMware is not an operating system vendor and platform support is therefore based on customer demand and subject to the principles of free market economics.

Naturally, vCenter provides important configuration and management capabilities such as DRS and performance monitoring.  If an environment cannot tolerate vCenter downtime, there are several methods that can be used to increase availability, from VMware HA, to MSCS clustering, to the high-end vCenter Server Heartbeat.  Even if you don’t implement any of those measures and disaster strikes, it is relatively quick and easy to rebuild vCenter and bring live VMware ESX hosts back under management with zero impact on running VMs.

Dare to Compare

If you have not tried VMware vSphere 4, download your free 60-day evaluation with all Enterprise Plus features and capabilities today.  I would say put it head-to-head against Red Hat Enteprise Virtualization, but since no evaluation version is available, that may be difficult.

If your datacenter needs the most reliable virtualization platform with the broadest support for guest operating systems — including Red Hat Enterprise Linux — and the best management capabilities in the industry, go with VMware vSphere.

Related posts:

1. Red Hat Enterprise Virtualization HA [ha ha]
2. What is Red Hat Enterprise Virtualization?
3. Red Hat Enterprise Linux is not Enterprise Virtualization
4. RHEV Wrap-Up

• RHEV Hypervisor (RHEV-H) — slimmed-down to run just the KVM Linux kernel modules and supporting services
• Red Hat Enterprise Linux 5.4 (RHEL) — full installation with any applications, GUIs, or tools desired

By paying $749/socket for RHEV, users are entitled to use RHEV-H for no additional cost.  However, those that opt to use the full installation of RHEL 5.4 must purchase an appropriate RHEL subscription separately, which typically runs $1299-$2499 per host.

Wow, the cost of all this open source virtualization technology can really add up!

Red Hat Enterprise Confusion

A full installation of RHEL 5.4 provides necessary KVM Linux kernel modules and some basic management tools to create and run virtual machines — without a trace of RHEV:

However, don’t jump to the conclusion that such a RHEL 5.4 host can also be managed by the RHEV Manager — the KVM packages required by RHEV are different and incompatible with those provided in a standard RHEL 5.4 installation.  In fact, for some odd reason, even the command-line tools are unavailable or incompatible with RHEV — the only way to manage virtual machines is with the RHEV Manager.

Don’t just take my word for it, the Installation Guide says it best:

And don’t forget, the RHEV Manager runs exclusively on Windows and the only interface is Internet Explorer.  So much for open source virtualization management technologies.

VMware vSphere Consistency

One of the great strengths of VMware ESXi is the consistent management experience across a range of deployment options.  This is because the same exact bits are used for every edition of VMware ESXi — features are simply added by applying appropriate licensing.  In fact, the same exact vSphere Client connects to every edition of ESXi — from free to Enterprise Plus — as well as to VMware vCenter Server for centralized management.  This design offers a consistent virtualization management experience in every environment.

Red Hat Enterprise Virtualization offers no free edition and expects customers to contend with multiple incompatible variations of the same core hypervisor — each with a different management interface.  Somehow, I doubt that is what “customers are asking for.”

Treat your Red Hat Enterprise Linux workloads to the best — run them on VMware vSphere.

Related posts:

1. What is Red Hat Enterprise Virtualization?
2. Dear Red Hat…
3. Red Hat Enterprise Virtualization: Pentium II Inside!
4. Red Hat Enterprise Virtualization HA [ha ha]

Red Hat Enterprise Virtualization 2.1 (RHEV), released in November 2009, is a new product from Red Hat — essentially an update to the management tools acquired along with Qumranet in 2008.  RHEV consists of two main elements: RHEV Manager and RHEV Hypervisor.  RHEV Hypervisor is a slimmed-down version of RHEL 5.4 designed to function solely as a KVM hypervisor.

RHEV Manager, on the other hand, has nothing to do with Red Hat Enterprise Linux.  Unbelievably, the product runs exclusively on Windows Server 2003, is based on .NET, and is only accessible with Internet Explorer.  I know this sounds like Bizarro World, but it’s true!

One Hypervisor is not Enough?

Red Hat CEO, Jim Whitehurst — evidently borrowing some pages from the Microsoft Virtualization playbook — claims that customers want an alternative to VMware vSphere so they do not need to be completely dependent on one hypervisor.  Since it is practically impossible to get a single one of the thousands of satisfied VMware customers to replace their beloved vSphere with another platform, the only sensible approach is to promote a dual-vendor strategy.  No surprises there.

References?

If customers were actually asking for this, then you’d expect some of those alleged customers to be readily available as references.  So far there appears to be just one, a Swedish Internet video company named Voddler.  I’ve never heard of them either — but a reference customer is a reference customer, and name recognition isn’t everything!  I tried to find another reference, but after almost half a year since the RHEV 2.1 GA release there aren’t any.

Same or Better than vSphere?

Red Hat claims that RHEV is “…60-80 percent lower cost with the same or better features compared to other solutions.”

Same or better features than vSphere?  According to whom?

I’ve taken a close look at RHEV and will publish some of my findings soon — subscribe to the RSS feed if you want to follow along.

Related posts:

1. Red Hat Enterprise Linux is not Enterprise Virtualization
2. Red Hat Enterprise Virtualization: Pentium II Inside!
3. Red Hat Enterprise Virtualization HA [ha ha]
4. RHEV Manager — It’s not just a clever name