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Direct I/O Access

Direct I/O Access (Erl, Naserpour)

How can a virtual server overcome data transfer capacity thresholds imposed by its surrounding virtualization environment?

Problem

Virtualized networks and associated virtualized IT resources have capacity limitations that can unreasonably inhibit virtual server communication and data transfer performance.

Solution

The virtual server is allowed to circumvent the hypervisor and directly access the physical server's I/O card.

Application

The hypervisor transfers complete control of the physical server's I/O card directly to the virtual server, which is then able to recognize the I/O card as a hardware device.
Direct I/O Access: Part A (left) shows the virtual server accessing a database stored on a SAN storage LUN. Connectivity from the virtual server to the database occurs via a virtual switch. Part B (right) depicts an increase in the amount of requests. The resulting bandwidth and performance of the virtual NIC are inadequate.

Part A (left) shows the virtual server accessing a database stored on a SAN storage LUN. Connectivity from the virtual server to the database occurs via a virtual switch. Part B (right) depicts an increase in the amount of requests. The resulting bandwidth and performance of the virtual NIC are inadequate.

Direct I/O Access: In Part C, the virtual server bypasses the hypervisor to connect to the database server via a direct physical link to the physical server. The increased workload can now be properly handled.

In Part C, the virtual server bypasses the hypervisor to connect to the database server via a direct physical link to the physical server. The increased workload can now be properly handled.

NIST Reference Architecture Mapping

This pattern relates to the highlighted parts of the NIST reference architecture, as follows:

Direct I/O Access: NIST Reference Architecture Mapping
Direct I/O Access: NIST Reference Architecture Mapping