2 Replies Latest reply on Mar 24, 2014 1:22 AM by rachelsg

    VMware VMDirectpathI/O vs NPIV

    askvmware Novice



      What is the difference between VMDirectpath I/O and NPIV configurations in VMware ?


      As I understand, both can be used to present the HBAs directly to the guests.



        • 1. Re: VMware VMDirectpathI/O vs NPIV
          dhanarajramesh Expert

          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

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          • 2. Re: VMware VMDirectpathI/O vs NPIV
            rachelsg Enthusiast



            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.

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