Kernel-based Virtual Machine (KVM) vs. XenServer

Kernel-based Virtual Machine is very well suited when one needs a single-node virtualization host or needs to build a complex demo setting on their own notebook (e.g. when demonstrating solutions to a customer).

Incentivized

It can be really helpful & useful if we are using Citrix Hypervisor with other provisioning tools. Here are some specific scenarios where Citrix Hypervisor (formerly Citrix XenServer) is well-suited: Server Consolidation, Virtual Desktops, Disaster Recovery, Development & Testing Environments. On the other hand, there are some scenarios where Citrix Hypervisor may be less appropriate: Small-scale Deployments, Highly Heterogeneous Environments, and Limited Virtualization Requirements.

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• Lightweight built-in implementation for all *nix based OS.
• Easy to deploy and manage VMs.
• Freeware (is you are using a free OS).

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• Creating VMS - virtualizing physical or already virtual images is a snap
• Configuration - in a smaller environment, configuration is simple and easy to understand
• Templates and Clones - the ability to create these on the fly make it great for a dev environment

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• KVM itself doesn't ship with a management interface
• KVM itself is a bit complicated to handle
• KVM needs Qemu to virtualize Windows guests

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• Although part of this is free the free solution has limitations that make the purchase of the paid version a requirement for most medium and large enterprises.
• Support for USB devices is lacking vs. its competitors.
• Technical support is somewhat limited especially the free "Google browsing" type since the product is used much less vs. Hyper-V or VMWARE.
• In a related issue to tech support, finding local IT support who have used the product is also challenging.
• Networking/virtual networks are less stable than they should be.

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With the knowledge and usage of solutions from VMware and Microsoft offering more compelling cloud integrated options it makes it more compelling in many environments which I consult. XenServer is a good product and fits the bill in many smaller environments but as clients look to the cloud or a hybrid cloud it can in some cases make it a bit more difficult.

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It does the job and stays out of the way. The specifics of usability relies on the implementation, but with things like Icarus and libvirt, things are standardizing nicely.

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XenServer is a good product in its use and probably free if you have the right Citrix licenses already. However, it does require specific knowledge to manage, which makes it harder to manage if you don't have that knowledge in house.

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It's been a little problematic in the past at larger VDI deployments requiring a bit more care and feeding than other vendors. But the latest releases (6.5.x) have brought about huge improvements in the stability and availability.

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When running like a top XenServer is a fantastic hypervisor. There is relatively low overhead on the Dom0 so workloads get the most of the resources.

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The staff I've worked with are very knowledgeable or able to get a very well articulated and capable support team member on the phone or helping them if necessary and they always want to ensure the best experience possible for you on the platform. The ability for the support team to reach out to hardware vendors for assistance is a nice plus too.

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Part of a training for certification to become a trainer for Citrix included an in-person training with a Master CCI. The XenServer training at this time was pretty simplified due to the product primarily being installed however you did have to work with it and mildly configure the system.

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Haven't given it a real go with any online training however there are some options out there. I have taught a course following Citrix material for XenDesktop which leverages XenServer and it is pre-built so not the best for XenServer specifically for installation but configuration is mildly touched on

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Ensure you review the HCL (hardware compatibility list) and reach out to the hardware vendors to ensure they support the platform and in case they have documentation that can be followed for the implementation. Also ensure the prerequisites are completed prior to implementation so that as few unexpected delays occur as you can control.

Incentivized

The key points why I made my decision for KVM in comparison with VMWare are: Freeware software (I am using an Ubuntu server OS), Fewer resources usage, vSwitch using that provides the ability to configure dot1q trunks to/between VMs, Stability, and simplicity of using/troubleshooting, Well-known interface (for Linux geeks).

Incentivized

In the scheme of the real world, Citrix Hypervisor is used much less than the other two main competing products; MS Hyper-V and VMWare vSphere. So, choosing Citrix Hypervisor for your organization comes down to whether you are comfortable going with a lesser-used product. All 3 products offer hardware layered hypervisor installation which means no OS overhead headaches. That is usually positive but in some cases, with very small shops, the OS layer is needed to host other workloads so Hyper-V running on Windows is the better choice. We run both MS Hyper-V and Citrix Hypervisor and we chose the Citrix product for our testbed environment since any risk of running the less public supported product was lessened by not being in full production.

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The servers latest versions have made massive improvements to scalability. But from past experience there have been issues when running workloads for extended periods of time without reboot on the hosts. I would need to run similar workloads on the 6.5 release which has changed much of the bottlenecks or issues so I'd imagine its far more capable now, Perhaps able to stand near the best in the market.

Incentivized

• Capital expenditure costs are low, because is open-source and free
• Operational expenditure costs are medium because it's necessary [to have] an IT team with experience in Linux
• First step to the virtualization world. Wake up, we are in the 21st century

Incentivized

• Xenserver is easy to learn. We paid for support only for installation and deployment in the first three years, and now our team has the knowledge to solve most problems.
• Low CAPEX if you have a team that uses open source software day by day.
• But paid support is necessary to solve critical problems. The open source community is not enough. Actually, we have difficulty solving some bugs without paying for support.
• Medium OPEX if you have a team that uses open source software day by day.

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