Is KVM or Docker Faster for Server Virtualization?

Server and cloud administrators have long had multiple virtualization options to choose from. In 2014, Docker container virtualization has emerged as yet another choice and according to research from IBM, it could well be the best choice in terms of performance.

In the traditional hypervisor Virtual Machine (VM) approach that is used by VMware’s ESX and open-source options like Xen and KVM, a host operating system runs the hypervisors, which then in turn requires an operating system of its own for VMs. The Docker model is a bit different in that only the host operating system is required and containerized apps then run on top of that OS.

Delving into Docker’s Performance Advantages

The basic premise behind containers is a more optimized delivery approach. IBM’s report also found that containers present a performance boost as well.

“Our results show that containers result in equal or better performance than VMs in almost all cases,” the report states. “Both VMs and containers require tuning to support I/O-intensive applications.”

Using the Linpack performance metric, IBM’s researchers measured the performance impact of virtualization and found Docker containers to be the clear winner. The researchers found that Docker delivered near-native bare-metal performance while KVM performance was approximately 50 percent less.

“Performance is almost identical on both Linux and Docker – this is not surprising given how little OS involvement there is during the execution,” the report states. “However, the KVM performance is markedly worse, showing the costs of abstracting/hiding system information from the execution.”

Though the IBM research is very favorable to Docker, the report noted there are some performance hurdles. Docker’s NAT (Network Address Translation) is one such hurdle, adding in some performance overhead for high-packet rate data flows.

On the Fast Track to the Mainstream

Docker container technology was first launched as a public project in March 20 of 2013. Since then the project has reached its 1.0 milestone and is supported technology on Red Hat Enterprise Linux 7.

Docker is also inspiring a wave of new companies, including Docker Inc, that are building innovations around the open-source Docker technology. Docker Inc has its Docker Hub effort, which includes private repositories for developers. The CoreOS Linux project is building a commercial model around deploying highly available and clustered Docker server deployments at scale.

Other vendors in the Docker ecosystem include CenturyLink, which recently launched its Panamax Docker deployment technology, and ClusterHQ, which is building data-aware Docker technologies.

Sean Michael Kerner is a senior editor at ServerWatch and InternetNews.com. Follow him on Twitter @TechJournalist.

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