freebsd-skq/share/man/man4/nda.4
2019-02-23 09:34:57 +00:00

89 lines
2.7 KiB
Groff

.\"
.\" Copyright (c) 2017 Netflix, Inc.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\"
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\" $FreeBSD$
.\"
.Dd December 20, 2017
.Dt NDA 4
.Os
.Sh NAME
.Nm nda
.Nd NVMe Direct Access device driver
.Sh SYNOPSIS
.Cd device nvme
.Cd device scbus
.Sh DESCRIPTION
The
.Nm
driver provides support for direct access devices, implementing the
.Tn NVMe
command protocol, that are attached to the system through a host adapter
supported by the CAM subsystem.
.Sh SYSCTL VARIABLES
The following variables are available as both
.Xr sysctl 8
variables and
.Xr loader 8
tunables:
.Bl -tag -width 12
.It Va kern.cam.nda.sort_io_queue
.Pp
This variable determines whether the software queued entries are
sorted in LBA order or not.
Sorting is almost always a waste of time.
The default is to not sort.
.El
.Pp
The following report per-device settings, and are read-only unless
otherwise indicated. Replace
.Va N
with the device unit number.
.Bl -tag -width 12
.It Va kern.cam.nda.N.rotating
.Pp
This variable reports whether the storage volume is spinning or
flash.
It's value is hard coded to 0 indicating flash.
.It Va kern.cam.nda.N.unmapped_io
This variable reports whether the
.Nm
driver accepts unmapped I/O for this unit.
.El
.Sh FILES
.Bl -tag -width ".Pa /dev/nda*" -compact
.It Pa /dev/nda*
NVMe storage device nodes
.El
.Sh SEE ALSO
.Xr nvd 4 ,
.Xr nvme 4
.Sh HISTORY
The
.Nm
driver first appeared in
.Fx 12.0 .
.Sh AUTHORS
.An Warner Losh Aq Mt imp@FreeBSD.org