I/O Virtualization

Virtualization is the concept of separating a "function" — such as storage, memory or processing — from the underlying physical hardware — disks, DRAMs and CPUs. This allows the physical hardware to be pooled and shared across multiple applications — increasing utilization and capital efficiency — while maintaining the standard execution model for applications.

I/O Virtualization consists of three distinct steps:

1. Separation of I/O resources — providing management independence.
2. Consolidation of the I/O resources into pools — increasing the utilization, saving cost, power and space.
3. Virtualization — emulating the original I/O functions as "virtual" functions to avoid software disruption.

Separation

Instead of providing each server with internal dedicated I/O adapters, cables, network ports and disks, I/O Virtualization separates the physical I/O from the servers, leaving them as highly compact and space efficient pure compute resources such as 1U servers or server blades.

Consolidation

Once separated from the server, the I/O from multiple servers can now be consolidated into an I/O Virtualization Switch. Because the I/O components are now shared across many servers, they can be better utilized and the number of components is significantly reduced when compared to a non-virtualized system. The system becomes more cost, space and power efficient, more reliable — due to fewer components and architectural advantages such as RAID6 on the disks — and easier to manage.

Virtualization

The final step is to create virtual I/O devices in the servers which look to the server software exactly the same as the original physical I/O devices. This functional transparency preserves the end-users' huge investment in software: applications, OSs, drivers and management tools. The server hardware appears to the software to be exactly the same as today — the same I/O architecture, the same I/O devices, the same drivers all managed with the same tools — but with all the cost, space, power, dynamic configuration and manageability advantages which come with I/O consolidation.

Today all volume servers and I/O devices support PCI Express®. The PCI-SIG has recently defined a number of extensions to PCI Express to support I/O Virtualization capabilities both within a single server (SR-IOV) and across multiple servers (MR-IOV). These extensions however have not been fully transparent with respect to standard PCI Express and require new modified I/O devices.

Virtensys I/O Virtualization approach, although compatible with the PCI MR-IOV standard, is based on virtualizing the high volume off-the-shelf PCI Express I/O adapters available today. Virtensys I/O Virtualization technology is fully transparent to existing servers and I/O adapters and requires no changes to server or I/O hardware, device drivers or management tools. Being based on the native server I/O interconnect — PCI Express — it does not require any extra adapters or interfaces to other interconnects such as InfiniBand or 10 GE Ethernet.

Virtensys I/O Virtualization technology includes a high-performance PCI Express switch (IOVE) that has been enhanced to allow multiple servers to connect to the switch and hence for the I/O devices to be shared across many servers. In contrast with PCI-SIG MR-IOV — which requires changes to the I/O devices — the virtualization function in Virtensys technology is built into the PCI switch fabric in the form of a Virtualization Proxy Controller (VPC). The VPC is a Virtensys hardware device which works with the IOVE switch to virtualize multiple standard PCI Express I/O adapters.

The final component of Virtensys I/O Virtualization technology is the Virtensys Management Software (VMS) suite that provides the advanced I/O management capabilities. The VMS also provides out-of-band management of the PCI Express switching and virtualization capabilities and an execution platform for I/O vendors' standard management tools.

Hardware cost reduction through consolidation

The I/O subsystem can account for half of the acquisition cost of server hardware, and typically is over-provisioned and poorly utilized (~15%) to accommodate unpredictable I/O requirements of different applications. By consolidating the I/O from multiple servers, the utilization can be increased with fewer I/O devices required to support a given workload.

Power reduction

As with acquisition cost, increasing the I/O utilization through consolidation reduces the amount of I/O hardware required and corresponding power requirements.

Space reduction

Removing the need for servers to support physical I/O adaptors allows the increased use of high density 1U or blade server form factors, saving valuable rack and floor space.

Management simplification

I/O Virtualization changes server configuration from a hands-on, lights-on manual operation involving installation of adapters, cables and switches, to a software operation suitable for remote or automated management. By removing humans from the data center and providing automated validation of configuration changes, data center availability and reliability is enhanced.

Dynamic configuration — agility

Businesses today need to adapt quickly to change if they wish to prosper. Their IT infrastructure also needs to be agile to support rapidly changing workloads and new applications. IOV allows servers to be dynamically configured to meet the processing, storage and I/O requirements of new applications in seconds rather than days.

Ease of deployment and non-disruptive integration

Virtensys' PCI Express based I/O Virtualization technology has been design specifically to avoid any disruption of existing software, hardware or operational models in data centers. Virtensys I/O Virtualization works with — and is invisible to — existing volume servers, I/O adapters, management tools, OS and drivers, making its deployment in the data center simple and straightforward.

Compatibility with blade server architectures and form factors

By basing its I/O Virtualization technology on PCI Express, Virtensys has ensured compatibility with the architectures and strict space and power constraints of blade server chassis.

This technology also simplifies the management of blade servers by effectively removing the networking aggregation switches from the chassis and restoring the clean separation between server, storage and network management operations.

No performance "cost-of-virtualization"

Virtensys technology virtualizes I/O adapters directly at the PCI Express hardware level, ensuring that there is no "cost-of-virtualization" which has been seen in older software virtualization approaches.

Rapid and cost-effective adoption of new CPU and I/O technologies

The separation of I/O from the CPU and memory resources in servers allows new CPUs to be introduced quickly without disrupting the I/O subsystems. Similarly, new I/O technologies can be introduced as soon as they are available. Since these new high-cost and high-performance I/O adapters are shared across multiple servers, their introduction cost can be significantly smoothed when compared with today's deployment model.