IOIsolation

IO isolation, or input/output isolation, refers to techniques that separate input/output paths of processes, devices, or virtual machines to minimize interference and improve determinism, reliability, and security. It encompasses software-level mechanisms such as per-process I/O queues and quotas, as well as hardware-assisted methods including IOMMU-based device isolation and PCIe passthrough, and virtualization features like SR-IOV and virtual I/O channels.

In operating systems and virtualization, IO isolation is implemented through I/O scheduling, throttling, and resource controls that limit bandwidth per task or container. Hardware-assisted approaches use an IOMMU to map devices to specific VMs or namespaces, blocking unauthorized access. Storage and network subsystems implement QoS, queue discipline, and traffic shaping to bound latency and prevent congestion from one tenant affecting others.

Applications of IO isolation span cloud platforms, databases, and storage arrays, where it improves performance predictability, fault containment, and security. It is essential for multi-tenant environments and for enforcing service-level objectives. Practices include per-tenant I/O cgroups, disk quotas, and dedicated I/O channels or virtualized interfaces to separate workloads.

Benefits of IO isolation include reduced interference among workloads, improved reliability, and stronger security boundaries. Trade-offs involve added system complexity, configuration overhead, and potential underutilization due to conservative limits or rigid partitioning.

See also: I/O scheduling, IOMMU, QoS, cgroups, virtualization I/O.