nvme-compare(1)
===============

NAME
----
nvme-compare - Send an NVMe Compare command, provide results

SYNOPSIS
--------
[verse]
'nvme-compare' <device> [--start-block=<slba> | -s <slba>]
			[--block-count=<nlb> | -c <nlb>]
			[--data-size=<size> | -z <size>]
			[--metadata-size=<metasize> | -y <metasize>]
			[--ref-tag=<reftag> | -r <reftag>]
			[--data=<data-file> | -d <data-file>]
			[--metadata=<meta> | -M <meta>]
			[--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]

DESCRIPTION
-----------
The Compare command reads the logical blocks specified by the command
from the medium and compares the data read to a comparison data buffer
transferred as part of the command. If the data read from the controller
and the comparison data buffer are equivalent with no miscompares,
then the command completes successfully. If there is any miscompare,
the command completes with an error of Compare Failure. If metadata is
provided, then a comparison is also performed for the metadata.

OPTIONS
-------
-s <slba>::
--start-block=<slba>::
	64-bit address of the first block to access.

-c <nlb>::
--block-count=<nlb>::
	Number of blocks to be accessed (zero-based).

-z <size>::
--data-size=<size>::
	Size of data to be compared in bytes.

-y <metasize>::
--metadata-size=<metasize>::
	Size of metadata to be trasnferred in bytes.

-r <reftag>::
--ref-tag=<regtag>::
	Reference Tag for Protection Information

-d <data-file>::
--data=<data-file>::
	Data file.

-M <meta>::
--metadata=<meta>::
	Metadata file.

-p <prinfo>::
--prinfo=<prinfo>::
	Protection Information and check field.

+
[]
|=================
|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
|=================

-m <appmask>::
--app-tag-mask=<appmask>::
	App Tag Mask for Protection Information

-a <apptag>::
--app-tag=<apptag>::
	App Tag for Protection Information

-l::
--limited-retry::
	Number of limited attempts to media.

-f::
--force-unit-access::
	FUA option to guarantee that data is stored to media.

-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
	specifcation (1.3a) defines only one directive, 01h, for write
	stream idenfiers.

-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 lower 16 bits of the DSM field in a write
	command; the upper 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 optionn will be
	_ignored_.

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

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

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