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My exposure to virtualization has been limited to Virtualbox &VMware-player on Desktops, and to VMWare ESXi &KVM on Linux server, and exclusively with Linux guests (RHEL/CentOS). So please pardon my limited knowledge of Windows server -- terminology, product offerings etc.

My software product, is presently supported on RHEL6.4, on baremetal servers and also on virtual servers in VMWare ESXi & KVM. I am presently evaluating adding support for Microsoft Hyper-V, however reading the Wikipedia page, I learnt that Hyper-V is related-to/part-of MS Windows Server 2012-R2 and that it supports only up to RHEL6.3! On Microsoft website, I wastaken to the page for MS Windows Server 2012-R2, where it appears that Hyper-V is not a standalone virtualization product but perhaps part of Windows Server 2012-R2 (embedded feature?), and that MS Windows Sever 2012, needs to be in an active-partition of the baremetal server, for Hyper-V to be able to virtualize additional servers. Also, I read this comparison between Hyper-V and VMWare-ESXi. So my questions are:

  • Is my understanding correct that Hyper-V is not a standalone product ?
  • Is RHEL support limited to 6.3 only ? It is nearly a year that 6.4 was released, yet I didn't find any information on roadmap / support plan for Hyper-V for this guest OS, or did I miss anything ?
  • Is there no free version / evaluation version of Hyper-V (which one could use to try before buying) ?
  • Is what VMware writes in it's comparison, really true that to have Hyper-V you have a min. of 5GB and typically 10GB footprint of baremetal installation ?
  • Finally, there seem to be some serious performance concerns for someone moving from VMWare ESXi to Hyper-V. Is this true ?

I found a lot of resources on running Windows Server as guest VMs on Hyper-V, but very little on running Linux guest VMs on Hyper-V, which leads me to think that Hyper-V is perhaps not so well suited for the latter purpose (running Linux guests). While the answer may be somewhat open-ended and more of an opinion, but if someone can provide clear reading material that discusses these aspects, in a neutral manner, would really appreciate.

bdutta74
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  • There are two versions of Hyper-V. One, as you say, is a role that can be added to any normal Server 2012 install, and the other is a baremetal install. The stand-alone .iso (as a trial) can be downloaded from [TechNet here](http://technet.microsoft.com/en-gb/evalcenter/dn205299.aspx). – tombull89 Jan 21 '14 at 13:05
  • Actually this is one version of Hyper-V - as the technology is identical. Hyper-V is also in Windows CLIENT (not server) starting with 8.1 - so you can try it out without a separate server. VERY handy for certain developer scenarios. – TomTom Jan 21 '14 at 14:58

2 Answers2

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Is my understanding correct that Hyper-V is not a standalone product ?

Yes and no. Hyper-V is a technology. It is available as component of WIndows Server AND as a standalone product (Hyper-V Server) - the later one being free.

Is RHEL support limited to 6.3 only ?

Ask Redhat. THAT SAID (I am a MS guy) the components for Hyper-V support are now part of the Linux Kernel. If Redhat runs on a MODERN (current) kernel, everything is implicitly in it due to that.

That said, 6.5 seems to be supported according to Microsoft: http://social.technet.microsoft.com/Forums/windowsserver/en-US/efa52a15-6db9-4e65-97e4-af8a969ebe28/centosrhel-65-on-hyperv-2012-r2?forum=linuxintegrationservices

Note the answer is official fromsomeone at Microsoft.

Is there no free version / evaluation version of Hyper-V (which one could use to try before buying) ?

As I said - there is a free Hyper-V server but there also are WIndows Server time limited trials IIRC.

A small google (you may want to use them sometimes) turned me directly to:

http://www.microsoft.com/en-us/server-cloud/products/windows-server-2012-r2/default.aspx

what I looked for btw. was "WIndows Server Evaluation". Not exactly a not obvious search term to get an evaluation version. Not the "Try" button on the website.

Is what VMware writes in it's comparison, really true that to have Hyper-V you have a min. of 5GB and typically 10GB footprint of baremetal installation ?

Yes. It also is much better supported than VMWare on hardware as it runs on any hardware windows runs while with VMWare you are really in for a "get the hardware on the compatibility list or go home" treatment. It also is patched WITH windows (always being a windows component - the free version hyper-v server is basically a WIndows server missing most compnonents). Generally, for a windows shop a Hyper-V server is a LOT easier to maintain than a VMWare thing because it integrates very well with the patch infrastructure. For a developer the hardware freedom is great - you can get Hyper-V running on pretty much all current laptops, the same is not true with VmWare. And there are people using that on a laptop for development / demonstration.

Finally, there seem to be some serious performance concerns for someone moving from VMWare ESXi to Hyper-V. Is this true ?

Let me formulate it like that - where did you get that hogwash from? I know there are performance differences, but this is the first time I hear of "serious performance concerns" that are not immediately disqualifiable. BOTH run a hardware level virtualization and the real differences are probably not worth it (i.e. below 5%).

TomTom
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  • "Hyper-V Server" is a Server Core edition of Windows Server where only the Hyper-V role is available; but it still is a Windows system, not some different product. – Massimo Jan 21 '14 at 13:55
  • Thanks much TomTom. That pretty much answers all of them, very well. I tried to search on MS website (via google), and clicking any link related to Hyper-V would take me to 'Windows Server 2012 R2' page, and it was getting a bit frustrating. The serious performance issues, on technical forums ranged from network i/o throughput issues to disk i/o throughput issues. More on a workload management front. However, now that I learnt of 'Hyper-V Server' being a free download, I will try it own myself, and see how it fares for my software - since that is all I care about. – bdutta74 Jan 21 '14 at 13:55
  • It can be Hyper-V server 2012 R2 is not available yet - 2012 R2 server is very new and sometimes the related products take some months. Now, network and disc IO - no issues. As in: if you know what you do and have decent hardware. Obviously a large slow disc gets overloaded when you start 10 vm's from it ,but that is not hyper-v's fault. Note that disc is the most overlooked issue of all and any virtualization - most people never plan for proper disc performance. We run Hyper-v also against a 10g network and have no performance issues. And yes, that is virtual - a file server delivering a load – TomTom Jan 21 '14 at 14:56
  • ...to 6gigabit that is a VM and serving a hpc cluster with raw data. So, network and disc are fine - if you buy appropriate hardware. Rand - broadcom network drivers are kNOWN to be - ah - "interesting". They are creative, sometimes, in reinterpreting microsoft interface documentation with the result that - the results are - interesting ;) – TomTom Jan 21 '14 at 14:57
  • FOR TESTING: Hyper-V now is also available in Windows 8.1 or higher ;) No need to install a server. THis is a hugh advantage compared to vmware - especially when you talk about developers and laptops and the need to run a VM on them ;) – TomTom Jan 21 '14 at 14:59
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Here are some answers for you:

  • Yes, Hyper-V is part of the Windows operating system, it's not a standalone product.
  • RHEL guests are fully supported up to version 6.4 on Hyper-V systems, both the ones based on Windows Server 2012/R2 and the previous ones based on Windows Server 2008 R2.
  • There is a free version of Hyper-V; is called "Hyper-v Server" and is freely available to download and run; it's a stripped-down version of Windows Server which only supports the Hyper-V role. You can find it here.
  • However, the parent OS is still a full (or semi-full) Windows Server system, thus it obviously has a bigger footprint than ESXi.
  • Performance can differ between hypervisors, but not so much; talking about "serious performance concerns" really smells of propaganda. Anyway, you should of course perform some load tests and see for yourself.
Massimo
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  • Wrong. Get Hyper-V server for example, you even say so yourself). And 6.5 IS supported (http://social.technet.microsoft.com/Forums/windowsserver/en-US/efa52a15-6db9-4e65-97e4-af8a969ebe28/centosrhel-65-on-hyperv-2012-r2?forum=linuxintegrationservices) – TomTom Jan 21 '14 at 13:08
  • Uh? What is wrong, exactly? – Massimo Jan 21 '14 at 13:09
  • Thanks for answering Massimo. Does your first bullet-point somewhat contradict the 3rd bullet point, i.e. there is a "stripped down version", but no "standalone product" ? Perhaps that is what @TomTom cites as what could be construed as wrong. – bdutta74 Jan 21 '14 at 13:47
  • And, since a free version "Hyper-V Server" is indeed available for installation on bare-metal, I am certainly going to do through testing (including performance test) of my software on each of these VM technologies. – bdutta74 Jan 21 '14 at 13:48
  • The free "Hyper-V Server" actually is a stripped-down version of Windows Server, where only the Hyper-V role is available and all other roles and services can't be used. But it still is a Windows system, not some different product. – Massimo Jan 21 '14 at 13:54
  • Also Massimo, I understand that the free edition (Hyper-V Server 2012) is only community supported. If someone wants to purchase support for this "stripped down" version (because I want a lean setup), is it possible ? As for the free edition, is it really free-to-use or free-to-evaluate, since download link takes me to Eval-center. – bdutta74 Jan 21 '14 at 14:19
  • Yes, it's completely free and doesn't have any time or use restrictions; it even supports clustering and centralized management (using System Center Virtual Machine Manager). I don't know about support, though; you should ask Microsoft about that. – Massimo Jan 21 '14 at 14:25