Xen or ESXi?

I'm looking into virtualizing, if nothing else to learn. Would like a pfsense router and a minecraft server running virtual on one box. And whatever else I can come up that is worth virtualizing.

I prefer open source so naturally I'm looking at Xen on top of Debian. However I see many always talking about ESXi.

What are the pros / cons to each? Xen seems to be cli only which I'm comfortable with as I can ssh in and run headless. Haven't looked at ESXi yet as I don't know if I could launch a VM with it to see what it's all about ( Don't know the settings to use in VirtualBox. )

Any reason why you're not considering KVM?

Many people use VMWare (ESXi is VMWare) for virtualization but VMWare these days is owned by EMC and EMC doesn't play nice.

So if it were me I'd consider Xen or KVM before VMWare simply so there's no EMC tie in.

We actually use MS Hyper-V (not my choice) for the most part and don't have issues with it.

Didn't know KVM was a virtualization solution. Looking into it now.

ESXi has commercial support and could supply an organization with some advanced features that a newbie may never need. It is what is termed bare metal.

Xen may limit your clients. I could be wrong but at one time it didn't fully support windows.

KVM and it's base Qemu are pretty popular but may not be as fast as esxi. May be able to support unusual/different hardware too.

Solutions like other vmware products and virtualbox may be useful.

Proxmox may be used as well.

http://virtualization.findthebest.co...l-%28Type-1%29

As well as other choices. http://virtualization.findthebest.com/

If one is using Debian they probably aren't looking for commercial support. While the Hypervisor might be supported the Debian OS very likely isn't.

One can get a "supported" KVM by running RHEL as the Hypervisor.

The Linux guests still wouldn't necessarily be "supported" on any hypervisor if they're not RHEL or Suse. (Of course Canonical makes Ubuntu and does its own support of that but I wouldn't be using that if "support" were important to me.) If support isn't important going the Ubuntu route might make sense if one wanted some vestige of support and liked the Debian vs RedHat/Fedora way of doing things. If all the support will be in house then choosing Debian may be the way to go.

Go with Xen. Runs all operating systems, has full windows support (use GPLPV drivers for extra PV additions, such as VirtIO with networking, storage and ACPI).

I'm running environments with VMWare, Xen and a few with KVM, Xen has the best memory and device performance (doing a lot of VT-d here), KVM is good with Linux speed but not much else, VMWare is annoying as you are stuck with what "they" support, and it's not much.

Don't know why anyone would want to use Hyper-V, with closed-source hypervisors it's worse than VMWare, and you can use Xen (and KVM) for free (money and speech) and run anything on top of that.

I'm not quite sure about Windows support with KVM, I only have Linux with KVM, no Unices or Windows. With Xen Linux, BSD, Windows, it all just works, and fast too. It's also reliable, some offline servers that do not need security patching have uptimes for over 3 years.

Another neat thing is that it integrates nicely with Debian (but RPM based distros work too) and you can just install and manage it like any other package. Works great with puppet so you can automatically deploy hypervisors, and with the many Xen management GUI's, you should be able to manage it just as simple as the closed source stuff. (But I prefer the command line, I used the older one, "xm" for a very long time, only recently switched to the newer "xl" which is great too, I have no professional experience with the enterprise version, "xe").

If you have the right infrastructure, go with the open source version in the repo's of your distro of choice. If not, get the official XenServer with a SLA. Not sure if SLA's exist for KVM.

KVM fully supports Windows. Just about the only thing I've seen not supported OS-wise lately is Free BSD, and that's only with RHEL 6.5. If you were to run a Fedora 20 KVM hypervisor Free BSD works just fine (a cpu instruction issue in RHEL 6.5).

So in the world of open-source and free hypervisor, KVM is king, imo. I use it daily in several environments.

SLAs exist for KVM for subscribers of RHEL. Not so for Fedora or any other Red Hat OS that doesn't have support, such as CentOS. F those, you need community support from upstream.

Originally Posted by GaWdLy KVM fully supports Windows. Just about the only thing I've seen not supported OS-wise lately is Free BSD, and that's only with RHEL 6.5. If you were to run a Fedora 20 KVM hypervisor Free BSD works just fine (a cpu instruction issue in RHEL 6.5). So in the world of open-source and free hypervisor, KVM is king, imo. I use it daily in several environments. SLAs exist for KVM for subscribers of RHEL. Not so for Fedora or any other Red Hat OS that doesn't have support, such as CentOS. F those, you need community support from upstream.

This basically means that KVM cannot be SLA'ed as a separate product. But what makes KVM king? I've found that it is rather limited when compared to Xen, especially under memory pressure and high I/O, plus you can't create a driver domain to isolate devices from every host, which can be quite a security issue. I've also found that PCIe hot plug, USB hot plug and CPU hot plug and memory 'hot plug' which is pretty much just expansion isn't working properly in most cases. Don't get me wrong, I like KVM, but it really depends on your needs and environment.

But I think most people can agree that ESXi is no longer a good choice with Xen and KVM in the mix, it simply isn't flexible enough, costs tons of money, and the only advantage you might have is it's suite of management tools, which is a pretty stupid one since you'll be vendor-locking yourself in, and VMWare knows it. If you use something like Chef or Puppet, you can pretty much administer Xen or KVM like any other service. In terms of performance and compatibility, EXSi has nothing to offer.

Originally Posted by johnkeates This basically means that KVM cannot be SLA'ed as a separate product.

That is correct. It's just part of the OS to Red Hat.

But what makes KVM king? I've found that it is rather limited when compared to Xen, especially under memory pressure and high I/O, plus you can't create a driver domain to isolate devices from every host, which can be quite a security issue. I've also found that PCIe hot plug, USB hot plug and CPU hot plug and memory 'hot plug' which is pretty much just expansion isn't working properly in most cases. Don't get me wrong, I like KVM, but it really depends on your needs and environment.

I haven't run into memory pressure or I/O issues with KVM, though I don't punish my environments. I know of quite a few enterprise customers who rely on KVM in production environments, as well. I assume-as you mention-that it all depends on your needs and environment, and that they've tuned around those issues.

I like KVM for my single server test environment, and my laptop for quick testing, so I don't ask it to do a whole lot. Ease of access, ease of use-install from stock RHEL or CentOS repos, install virt-manager, and you're GTG-and performance in non-high performance computing situations (such as the aforementioned laptop hypervisor). These are some of the huge pluses of KVM.

Also, using a stock RHEL kernel is a big bonus for me.

But I think most people can agree that ESXi is no longer a good choice with Xen and KVM in the mix, it simply isn't flexible enough, costs tons of money, and the only advantage you might have is it's suite of management tools, which is a pretty stupid one since you'll be vendor-locking yourself in, and VMWare knows it. If you use something like Chef or Puppet, you can pretty much administer Xen or KVM like any other service. In terms of performance and compatibility, EXSi has nothing to offer.

Even RHEV with upcoming Satellite offerings for provisioning and Puppet integration are starting to make more sense than ESXi in some cases. VMware has always been one of my favorite products for production virtualization, but when we start looking at priceerformance...well, I think VMware might have outgrown their once mighty reign over the space.

We were a primarily Vmware shop. But the costs for Vmware Virtual Center and Vmotion were too expensive to continue down that road. We ended up moving to the free version of Citrix Xenserver which fitted our needs perfectly.

The licensing, which we haven't needed yet, turned out to be a pittance compared to Vmware. It was very surprising.

I also like Openstack, and have a dev setup to test it. http://www.ubuntu.com/cloud/ubuntu-openstack

I left a VMware shop last year. Their licensing was so inflexible and so costly that we looked for alternatives. Unfortunately, none really would have made an easy transition at the time, so we paid the fees. RHEV would be a cheap alternative, and with the current version does most of what we would have needed, but 2 years ago it was very different.

I think VMware player/workstation on a windows machine is cheap/free and works well, still. KVM for Fedora or Red Hat is free for the former, and relatively inexpensive for the latter, so it would be my current choice.

Point is: there are loads of great free/cheap alternatives to VMware these days!

I do appreciate all the input. As this is a home server / lab type of thing for fooling around I am finding that KVM on Debian with remote access via virt-manager is everything I could ask for and more. Will look at Xen later but for now this is doing me just fine for my purposes.

I used both and Recommended XenServer. It is so nice and worked really.

One more vote for Xen. Xen & Linux are a perfect match. VMware/ESXI is very proprietary IMHO

The problem is not Commercial or proprietary. XenServer have Commercial versions too but The problem is Freedom and compatibility. For example, If you have a powerful PC and make a Raid on it, VMware ESXi can't detect it very nice but Xen worked with it as a Gear.
XenServer have a very nice and Sexy support. You can Test it but Vmware can't.
Vmware steal Linux features too. For example, According to the Wikipedia Vmware tell you "VMWare dropped development of ESX at version 4.1, and now uses ESXi, which does not include a Linux kernel" but you can see SElinux and etc on ESXi.
You can't compare XenCenter with Vmware Vsphere client too. Vsphere is silly