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NVMF(4) Kernel Interfaces Manual NVMF(4) NAME nvmf -- NVM Express over Fabrics host driver SYNOPSIS To compile the driver into the kernel, place the following line in the kernel configuration file: device nvmf Alternatively, to load the driver as a module at boot time, place the following line in loader.conf(5): nvmf_load="YES" DESCRIPTION The nvmf driver provides the kernel component of an NVM Express over Fabrics host. The NVMeoF host is the client which provides local ac- cess to namespaces exported by a remote controller. Associations between the local host and remote controllers are managed using nvmecontrol(8). New associations are created via the connect command and destroyed via the disconnect command. If an association's connection is interrupted, the reconnect command creates a new associa- tion to replace the interrupted association. Similar to nvme(4), nvmf creates controller device nodes using the for- mat /dev/nvmeX and namespace device nodes using the format /dev/nvmeXnsY. nvmf also exports remote namespaces via the CAM nda(4) peripheral driver. Unlike nvme(4), nvmf does not support the nvd(4) disk driver. Associations require a supported transport such as nvmf_tcp(4) for as- sociations using TCP/IP. SYSCTL VARIABLES The following variables are available as both sysctl(8) variables and loader(8) tunables: kern.nvmf.fail_on_disconnection Determines the behavior when an association's connection is in- terrupted. By default, input/output operations are suspended while a host is disconnected. This includes operations pending at the time the association's connection was interrupted as well as new requests submitted while the host is disconnected. Once a new association is established, suspended I/O requests are retried. When set to 1, input/output operations fail with EIO while a host is disconnected and nda(4) peripherals are de- stroyed after the first failed I/O request. Note that any de- stroyed nda(4) peripherals will be recreated after a new asso- ciation is established. SEE ALSO nda(4), nvme(4), nvmf_tcp(4), nvmft(4), nvmecontrol(8) HISTORY The nvmf module first appeared in FreeBSD 15.0. AUTHORS The nvmf driver was developed by John Baldwin <jhb@FreeBSD.org> under sponsorship from Chelsio Communications, Inc. FreeBSD 15.0 May 7, 2025 NVMF(4)
NAME | SYNOPSIS | DESCRIPTION | SYSCTL VARIABLES | SEE ALSO | HISTORY | AUTHORS
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