Brendan Gregg from Joyent has written an in-depth post on performance characteristics of three virtualization technologies: Zones, Xen, and KVM. According to Gregg, Zones add no overhead, whereas Xen and KVM do, which could limit network throughput to a quarter of what it could be.
By default we encourage customers to deploy on Zones, for reasons of performance, observability, and simplicity (debuggability). This may mean compiling their applications for SmartOS (our illumos-based OS which hosts the Zones) if they aren’t already in the repo. In cases where they absolutely must have Linux or Windows, and the applications can’t run elsewhere, then it’s Hardware Virtualization (KVM).
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