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Implementing IOV-capable adapters will require top-of-rack I/O virtualization units and either PCIe bus extender cards or InfiniBand HCAs for the host servers, depending on the implementation. The IOV-capable adapters are then placed in the top-of-rack IOV units and can be shared across servers. Drivers for these adapters will be needed, and few production-ready drivers for any operating system are currently available.
I/O virtualization should be implemented in stages, as with the adoption of any other new technology. The IOV implemented stages should begin with pilot tests run on a small number of servers; the pilot implementation should run until the products operate in a stable manner and benefits can be shown. The Demartek lab will be testing various IOV solutions during 2010, and we'll be able to provide first-hand commentary and results.
A good candidate environment for I/O virtualization might be a virtual server environment that would benefit from sharing some higher-end 10 GbE NICs or similar high-speed adapters. One of the goals of IOV implementations may be to acquire the necessary I/O adapters based on the overall bandwidth needs of all the servers in a rack, rather than simply buying adapters based on raw server count. This will require adjustments to the planning process to account for applications and bandwidth usage, and may require more bandwidth measurements to be taken in the current environments.
Management issues with I/O
Managing virtual pools of I/O resources will require some new thinking. The adjustment is similar to what was required to effectively manage storage systems when SANs and virtualized storage solutions were first deployed. You'll need to understand that the I/O adapters and paths will no longer be exclusively owned by a particular server, in the same way that storage on a SAN isn't owned by a specific server. Rather, these adapters and paths will be dynamically assigned to servers, and can be released or adjusted as needed. Each of the vendors providing top-of-rack IOV units will have their own management interface for the I/O virtualization unit itself, and some level of adapter management. In addition, each of the adapter manufacturers will provide some basic element manager, similar to what's provided today.
It remains to be seen how the operating systems and hypervisors will view these virtualized I/O adapters. Because ownership of the adapters will no longer be tied to a particular operating system or hypervisor, the management of these IOV resources will have to be aware that these resources can logically move around in the data center and that the I/O resources can have multiple personalities.
BIO: Dennis Martin has been working in the IT industry since 1980, and is the founder and president of Demartek, a computer industry analyst organization and testing lab.
This was first published in February 2010