nvme-cli/Documentation/nvme-read.txt

nvme-read(1)
============

NAME
----
nvme-read - Send an NVMe Read command, provide results

SYNOPSIS
--------
[verse]
'nvme-read' <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<storage-tag-check> | -C <storage-tag-check>]
			[--force]

DESCRIPTION
-----------
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't provide a file.

OPTIONS
-------
--start-block=<slba>::
-s <slba>::
	Start block.

--block-count::
-c::
	The number of blocks to transfer. This is a zeroes based value to
	align with the kernel's use of this field. (ie. 0 means transfer
	1 block).

--data-size=<size>::
-z <size>::
	Size of data, in bytes.

--metadata-size=<size>::
-y <size>::
	Size of metadata in bytes.

--data=<data-file>::
-d <data-file>::
	Data file. If none provided, contents are sent to STDOUT.

--metadata=<metadata-file>::
-M <metadata-file>::
	Metadata file, if necessary.

--prinfo=<prinfo>::
-p <prinfo>::
	Protection Information field definition.
+
[]
|=================
|Bit|Description
|3|PRACT: Protection Information Action. When set to 1, PI is stripped/inserted
on read/write when the block format's metadata size is 8. When set to 0,
metadata is passes.
|2:0|PRCHK: Protection Information Check:
|2|Set to 1 enables checking the guard tag
|1|Set to 1 enables checking the application tag
|0|Set to 1 enables checking the reference tag
|=================

--ref-tag=<reftag>::
-r <reftag>::
	Optional reftag when used with protection information.

--app-tag-mask=<appmask>::
-m <appmask>::
	Optional application tag mask when used with protection information.

--force-unit-access::
-f::
	Set the force-unit access flag.

-T <type>::
--dir-type=<type>::
	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.

-S <spec>::
--dir-spec=<spec>::
	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's capabilities.

-D <dsm>::
--dsm=<dsm>::
	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.

-v::
--show-cmd::
	Print out the command to be sent.

-w::
--dry-run::
	Do not actually send the command. If want to use --dry-run option,
	--show-cmd option _must_ be set. Otherwise --dry-run option will be
	_ignored_.

-t::
--latency::
	Print out the latency the IOCTL took (in us).

--storage-tag=<storage-tag>::
-g <storage-tag>::
	Variable Sized Expected Logical Block Storage Tag(ELBST).

--storage-tag-check=<storage-tag-check>::
-C <storage-tag-check>::
	This bit specifies the Storage Tag field shall be checked as part of end-to-end
	data protection processing.

--force::
    Ignore namespace is currently busy and performed the operation
    even though.

EXAMPLES
--------
No examples yet.

NVME
----
Part of the nvme-user suite