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Cornerstones of Virtualization: I/O Virtualization Defined

Input/Output (I/O) devices include disks, networks, CD-ROMs, consoles, etc

Pete Manca's Blog

Recently I talked about what I see as the next "waves of virtualization" taking the industry, I talked about I/O Virtualization as a key (maybe THE key) cornerstone, so I thought it might make sense to describe just what it is and why it's important.
Like all forms of virtualization, the physical world is masked and abstracted into a virtual representation, allowing for higher utilization or increased agility, etc. For IO, the physical world is typically defined by dedicated connections to Input/Output (I/O) devices such as disks, networks, CD-ROMs, consoles, etc.

In the enterprise, these devices can themselves be already virtualized (think Storage Area Networks) but their connectivity is typically very static – e.g. a fiber channel adapter connected to a specific port on a SAN switch.

I/O Virtualization abstracts the connectivity so the server itself is no longer statically configured to specific I/O wiring. This adds tremendous value to the enterprise. The most obvious benefit is that change management becomes easy. No longer do techs have to fish wire and re-wire data centers because server-to-I/O affinity has changed. With virtualization, the wiring stays static but the actual mapping between the server and the IO devices can be dynamic.

And this is just the beginning. I/O Virtualization also allows for easy server re-purposing, as a server can be “re-wired” to attached to different volumes on a SAN device or different networks, thus changing its personality or its life cycle (e.g. moving from test networks to production networks).

I/O Virtualization also enhances Server Virtualization, as it makes it easier for hypervisors to support migration – no need for clunky clustered file systems or open zoned SANs, which can expose serious security issues.

Taken even further, I/O Virtualization can help with Disaster Recovery. When the server is abstracted away from its I/O connectivity, it becomes very simple to move a set of servers (and their applications) to a remote site and quickly re-create the I/O environment. Something that can take weeks in the physical world can literally take minutes now.

So, hopefully you can see why I/O Virtualization is such a key cornerstone technology in the continued virtualization evolution. Be aware, though, that not all I/O Virtualization is created equal. IO/ Virtualization is not done by adding new layers of unmanaged hardware into the mix (think NPIV) and I/O Virtualization is not simply re-programming network and SAN switches as some would have you believe. It’s really about creating an agile abstraction layer that truly disassociates servers with their I/O devices, allowing for total flexibility in the data center.

More Stories By Pete Manca

Pete Manca is CTO and EVP of Engineering, Egenera. He brings over 20 years' experience in enterprise computing to Egenera. His expertise spans a wide range of critical enterprise data center technologies including virtualization, operating systems, large-scale architectures and open standards. In particular, his leadership and experience in virtualization technologies has led to the continued progression of Egenera's advanced PAN (Processing Area Network) architecture. Manca leads product planning by working directly with customers to understand their most difficult challenges and guide Egenera's architecture, hardware and software engineering teams to translate those requirements into solutions. Prior to Egenera, he served as Vice President of Engineering at Hitachi Computer Products America with responsibility for operating systems and enterprise middleware products.

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Most Recent Comments
Virtualization Manager 04/06/08 11:46:45 PM EDT

Trackback Added: The advantages of I/O Virtualization; Pete Manca explains the time/cost saving benefits of being able to “rewire” servers on the fly through virtualization, reducing downtime by using dynamic mapping.

Cornerstones of Virtualization: I/O Virtualization Defined
— Recently I ta...