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Virtualized I/O Can Now Include Local Storage

For organizations that deal with a large amount of connectivity, managing I/O that reins in port and device costs is a complicated task. For virtualization implementations, there are a number of ways to tackle this challenge. Some organizations avert fibre channel by focusing on Ethernet-based storage protocols such as iSCSI and NFS. Another strategy is to use blade servers to consolidate servers to a chassis that can have in-chassis switching and storage I/O delivered via a limited number of ports.

In spite of this, we still see a large number of virtualization implementations using rack-mount servers in favor of blades and fibre channel storage in lieu of an Ethernet-based storage protocol. In these situations, organizations can consider consolidating I/O to cut costs in central switching (ports) and achieve better utilization for this connectivity.

Recently, I reviewed parts of the Virtensys virtualized I/O solution. I’ve mentioned virtualized I/O on this blog before after having seen the Xsigo solution as well. The Virtensys solution delivers virtualized I/O differently. For one, Infiniband is not used to deliver the virtualized I/O. Instead, standard host bus adapters, network interfaces and other PCI-Express local devices can be used as the server endpoint device to receive the virtualized I/O.

The other distinguishing feature is that local storage can be managed with virtual I/O. Specifically, the storage that is local or direct attached on a server can be presented back to the Virtensys I/O virtualization engine. Fibre channel storage as well can be delivered through the virtualized I/O. The new VIO 4008 controller concurrently virtualizes Ethernet, fibre channel and local storage.

The typical implementation is a top-of-rack solution, where each server in the rack connects to the I/O virtualization switch for the networking and storage connectivity. The Virtensys technology has a limited compatibility list, but that surely will increase over time.

Virtualized I/O can appeal to certain situations, typically driven by port cost. Virtualized I/O can raise a lot of questions in security circles, however. Frequently the debate of whether or not Layer-2 separation is "good enough" is amplified in this situation as the same physical media could potentially transport multiple security zones of network traffic while simultaneously transporting multiple integrity zones of data.

What is your take on virtualized I/O? Share your comments here.

Posted by Rick Vanover on 01/21/2010 at 12:47 PM


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