VMDirectPath allows guest operating systems to directly access an I/O device, bypassing the virtualization layer. This direct path, or passthrough can improve performance for VMware ESX systems that utilize high-speed I/O devices, such as 10 Gigabit Ethernet. A single VM can connect to up to two passthrough devices. - pre-request are According to the vSphere 5 documentation there are several prerequisites that must be taken care of, before any VMDirectPath can be setup. The virtual machine must be on hardware version 7 or later. Intel® Virtualization Technology for Directed I/O (VT-d) or AMD I/O Virtualization Technology (IOMMU) enabled in the BIOS of the host. PCI Devices are connected to the host and marked for passthrough
N_Port ID virtualization (NPIV) is a technology that defines how multiple virtual servers can share a single physical Fibre Channel port identification (ID). NPIV allows a single host bus adaptor (HBA) or target port on a storage array to register multiple World Wide Port Names (WWPNs) and N_Port identification numbers. This allows each virtual server to present a different world wide name to the storage area network (SAN), which in turn means that each virtual server will see its own storage -- but no other virtual server's storage. simply we can say your VMware ESXI hypervisor would act as proxy to your VM guests
1 person found this helpful
Welcome to the communities.
As your question
VMDirectPath I/O is a VMware technology that can be used with I/O hardware to reduce the CPU impact of high-bandwidth throughput workload's by ‘‘bypassing’’ the hypervisor. By allowing virtual machines to directly access the underlying hardware devices, VMDirectPath I/O device access enhances CPU efficiency in handling workload's that require constant and frequent access to I/O devices
On the other hand NPIV is a Fibre Channel facility that enables one Fibre Channel adapter to have many N Port IDs.NPIV ports may not be used for booting. NPIV ports are best used in SANs with a relatively small number of ports, either virtual or physical. Not all hardware supports NPIV. Both switches and HBAs must support NPIV in a SAN.