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'\" t
.\" Title: nvme-read
.\" Author: [FIXME: author] [see http://www.docbook.org/tdg5/en/html/author]
.\" Generator: DocBook XSL Stylesheets vsnapshot <http://docbook.sf.net/>
.\" Date: 10/31/2024
.\" Manual: NVMe Manual
.\" Source: NVMe
.\" Language: English
.\"
.TH "NVME\-READ" "1" "10/31/2024" "NVMe" "NVMe Manual"
.\" -----------------------------------------------------------------
.\" * Define some portability stuff
.\" -----------------------------------------------------------------
.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.\" http://bugs.debian.org/507673
.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.ie \n(.g .ds Aq \(aq
.el .ds Aq '
.\" -----------------------------------------------------------------
.\" * set default formatting
.\" -----------------------------------------------------------------
.\" disable hyphenation
.nh
.\" disable justification (adjust text to left margin only)
.ad l
.\" -----------------------------------------------------------------
.\" * MAIN CONTENT STARTS HERE *
.\" -----------------------------------------------------------------
.SH "NAME"
nvme-read \- Send an NVMe Read command, provide results
.SH "SYNOPSIS"
.sp
.nf
\fInvme\-read\fR <device> [\-\-start\-block=<slba> | \-s <slba>]
[\-\-block\-count=<nlb> | \-c <nlb>]
[\-\-data\-size=<size> | \-z <size>]
[\-\-metadata\-size=<size> | \-y <size>]
[\-\-ref\-tag=<reftag> | \-r <reftag>]
[\-\-data=<data\-file> | \-d <data\-file>]
[\-\-metadata=<metadata\-file> | \-M <metadata\-file>]
[\-\-prinfo=<prinfo> | \-p <prinfo>]
[\-\-app\-tag\-mask=<appmask> | \-m <appmask>]
[\-\-app\-tag=<apptag> | \-a <apptag>]
[\-\-limited\-retry | \-l] [\-\-force\-unit\-access | \-f]
[\-\-dir\-type=<type> | \-T <type>]
[\-\-dir\-spec=<spec> | \-S <spec>] [\-\-dsm=<dsm> | \-D <dsm>]
[\-\-show\-command | \-V] [\-\-dry\-run | \-w] [\-\-latency | \-t]
[\-\-storage\-tag<storage\-tag> | \-g <storage\-tag>]
[\-\-storage\-tag\-check | \-C] [\-\-force]
[\-\-output\-format=<fmt> | \-o <fmt>] [\-\-verbose | \-v]
[\-\-timeout=<timeout>]
.fi
.SH "DESCRIPTION"
.sp
The Read command reads the logical blocks specified by the command from the medium and copies to the data data buffer provided\&. Will use stdout by default if you don\(cqt provide a file\&.
.SH "OPTIONS"
.PP
\-s <slba>, \-\-start\-block=<slba>
.RS 4
Start block\&.
.RE
.PP
\-c, \-\-block\-count
.RS 4
The number of blocks to transfer\&. This is a zeroes based value to align with the kernel\(cqs use of this field\&. (ie\&. 0 means transfer 1 block)\&.
.RE
.PP
\-z <size>, \-\-data\-size=<size>
.RS 4
Size of data, in bytes\&.
.RE
.PP
\-y <size>, \-\-metadata\-size=<size>
.RS 4
Size of metadata in bytes\&.
.RE
.PP
\-d <data\-file>, \-\-data=<data\-file>
.RS 4
Data file\&. If none provided, contents are sent to STDOUT\&.
.RE
.PP
\-M <metadata\-file>, \-\-metadata=<metadata\-file>
.RS 4
Metadata file, if necessary\&.
.RE
.PP
\-p <prinfo>, \-\-prinfo=<prinfo>
.RS 4
Protection Information field definition\&.
.TS
allbox tab(:);
lt lt
lt lt
lt lt
lt lt
lt lt
lt lt.
T{
Bit
T}:T{
Description
T}
T{
3
T}:T{
PRACT: Protection Information Action\&. When set to 1, PI is stripped/inserted on read/write when the block format\(cqs metadata size is 8\&. When set to 0, metadata is passes\&.
T}
T{
2:0
T}:T{
PRCHK: Protection Information Check:
T}
T{
2
T}:T{
Set to 1 enables checking the guard tag
T}
T{
1
T}:T{
Set to 1 enables checking the application tag
T}
T{
0
T}:T{
Set to 1 enables checking the reference tag
T}
.TE
.sp 1
.RE
.PP
\-r <reftag>, \-\-ref\-tag=<reftag>
.RS 4
Optional reftag when used with protection information\&.
.RE
.PP
\-m <appmask>, \-\-app\-tag\-mask=<appmask>
.RS 4
Optional application tag mask when used with protection information\&.
.RE
.PP
\-f, \-\-force\-unit\-access
.RS 4
Set the force\-unit access flag\&.
.RE
.PP
\-T <type>, \-\-dir\-type=<type>
.RS 4
Optional directive type\&. The nvme\-cli only enforces the value be in the defined range for the directive type, though the NVMe specification (1\&.3a) defines only one directive, 01h, for write stream identifiers\&.
.RE
.PP
\-S <spec>, \-\-dir\-spec=<spec>
.RS 4
Optional field for directive specifics\&. When used with write streams, this value is defined to be the write stream identifier\&. The nvme\-cli will not validate the stream requested is within the controller\(cqs capabilities\&.
.RE
.PP
\-D <dsm>, \-\-dsm=<dsm>
.RS 4
The optional data set management attributes for this command\&. The argument for this is the least significant 8 bits of the DSM field in a write command; the most significant 16 bits of the field come from the directive specific field, if used\&. This may be used to set attributes for the LBAs being written, like access frequency, type, latency, among other things, as well as yet to be defined types\&. Please consult the NVMe specification for detailed breakdown of how to use this field\&.
.RE
.PP
\-V, \-\-show\-cmd
.RS 4
Print out the command to be sent\&.
.RE
.PP
\-w, \-\-dry\-run
.RS 4
Do not actually send the command\&. If want to use \-\-dry\-run option, \-\-show\-cmd option
\fImust\fR
be set\&. Otherwise \-\-dry\-run option will be
\fIignored\fR\&.
.RE
.PP
\-t, \-\-latency
.RS 4
Print out the latency the IOCTL took (in us)\&.
.RE
.PP
\-g <storage\-tag>, \-\-storage\-tag=<storage\-tag>
.RS 4
Variable Sized Expected Logical Block Storage Tag(ELBST)\&.
.RE
.PP
\-C, \-\-storage\-tag\-check
.RS 4
This flag enables Storage Tag field checking as part of end\-to\-end data protection processing\&.
.RE
.PP
\-\-force
.RS 4
Ignore namespace is currently busy and performed the operation even though\&.
.RE
.PP
\-o <fmt>, \-\-output\-format=<fmt>
.RS 4
Set the reporting format to
\fInormal\fR,
\fIjson\fR
or
\fIbinary\fR\&. Only one output format can be used at a time\&.
.RE
.PP
\-v, \-\-verbose
.RS 4
Increase the information detail in the output\&.
.RE
.PP
\-\-timeout=<timeout>
.RS 4
Override default timeout value\&. In milliseconds\&.
.RE
.SH "EXAMPLES"
.sp
No examples yet\&.
.SH "NVME"
.sp
Part of the nvme\-user suite
|
