Comparative testing of LXD and KVM virtualization

LXD is a hypervisor by Canonical. It is an infrastructural container with a full-fledged Linux system. It works as if it were installed on a virtual or physical server. The LXD container is capable of replacing a KVM virtual machine.

Canonical has run a comparative test of LXD and KVM. An Intel server running on Ubuntu 14.04 LTS was used as the platform. During the tests on the equipment, the maximum number of guest LXD and KVM operating systems was launched.
Indicators tested were:

In the density test, the guest OS instances were automatically launched. As soon as the equipment resources ran out, the testing stopped. On the server with 16 GB RAM, they managed to launch 37 KVM and 536 LXD operating systems.

With LXD, the equipment is used more efficiently. This helps companies save money in the long term. For example, hosting providers will be able to provide customers with more guest operating systems on the same equipment.

536 OS on LXD started faster than 37 OS on KVM. On average, it took 1.5 seconds to launch one LXD instance and almost 25 seconds to launch one KVM instance.

LXD showed 57% lower latency than KVM.

Low latency is due to the fact that LXD does not require virtual environment emulation. Users get the benefit of container virtualization — the OS runs quickly as if it were deployed on a physical server.

With the LXD hypervisor, you can deploy guest operating systems on Linux, which are isolated as if hardware virtualization were used. At the same time, you will get high performance and density typical of container virtualization. LXD virtualization allows to use computing resources economically – more guest operating systems can be deployed on the same machine.