Virtualization shoot-out: Red Hat Enterprise Virtualization

Red Hat's server virtualization solution mixes ease and scalability with a few odd limitations

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Like Hyper-V, RHEV doesn't appear to take advantage of the AES-NI instructions in Intel Westmere processors, which accounts for the far lower crypto test results. And like Citrix XenServer, RHEV stumbled when the host was placed under significant load, the overall benchmarks of the VM under test dropping significantly. Hyper-V and VMware are better at handling wider loads than the others.

One significant benefit of RHEV is the ability to leverage multiple memory management technologies, including page sharing, memory compression, and ballooning. These features all have pros and cons -- page sharing may be better for server workloads, while ballooning is better for desktop VMs, for example -- but having all of these options available is a good thing.

The marriage of Qumranet and Red Hat is still in the early stages, and there's sure to be tighter integration with RHEL in the near future. As it stands now, RHEV exists on the edges of the overall Red Hat foundation. For instance, management agents are not yet available for RHEL virtual machines, though they are available for Windows. This means you can't issue a graceful shutdown command of an RHEL server from within RHEV, but must log into the server to perform the shutdown.

RHEV is sold on a subscription basis, which makes it initially cheaper than the alternatives. For 9-to-5 support, you can purchase RHEV for $499 per socket per year. A full farm of six dual-socket RHEV hosts will cost about $6,000 per year, and that price includes support and all upgrades as they are released.

Although RHEV certainly appears to be in a transitional phase, the underlying capabilities are strong, and current implementations of KVM outside of RHEV have progressed significantly beyond the ability of RHEV's management framework. This is evident in the advances made in KVM in RHEL 6, versus the version reviewed here, which is based on RHEL 5.6.1.

As time passes the delta between what KVM can do and what RHEV can manage should draw closer, providing a better, more cohesive overall product. Right now, RHEV is a stable and very functional server virtualization platform that offers many important features for a very attractive price.

Read the main article and the other reviews:

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Copyright © 2011 IDG Communications, Inc.

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