Cloud Computing Patterns, Mechanisms > Data Management and Storage Device Patterns > 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?
Virtualized networks and associated virtualized IT resources have capacity limitations that can unreasonably inhibit virtual server communication and data transfer performance.
The virtual server is allowed to circumvent the hypervisor and directly access the physical server’s I/O card.
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.
Burst In, Burst Out to Private Cloud, Burst Out to Public Cloud, Cloud Authentication, Cloud Balancing, Elastic Environment, Infrastructure-as-a-Service (IaaS), Isolated Trust Boundary, Multitenant Environment, Platform-as-a-Service (PaaS), Private Cloud, Public Cloud, Resilient Environment, Resource Workload Management, Secure Burst Out to Private Cloud/Public Cloud, Software-as-a-Service (SaaS)
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.
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: