SYNOPSIS

nvme get-feature <device> [--namespace-id=<nsid> | -n <nsid>]
                        [--feature-id=<fid> | -f <fid>]
                        [--uuid-index=<uuid-index> | -U <uuid_index>]
                        [--data-len=<data-len> | -l <data-len>]
                        [--sel=<select> | -s <select>]
                        [--raw-binary | -b] [--cdw11=<cdw11> | -c <cdw11>]
                        [--human-readable | -H] [--changed | -C]
                        [--output-format=<fmt> | -o <fmt>] [--verbose | -v]
                        [--timeout=<timeout> | -t <timeout>]

DESCRIPTION

Submits an NVMe Get Feature admin command and returns the applicable results. This may be the feature’s value, or may also include a feature structure if the feature requires it (ex: LBA Range Type).

The <device> parameter is mandatory and may be either the NVMe character device (ex: /dev/nvme0), or a namespace block device (ex: /dev/nvme0n1).

On success, the returned feature’s structure (if applicable) may be returned in one of several ways depending on the option flags; the structure may parsed by the program and printed in a readable format if it is a known structure, displayed in hex, or the raw buffer may be printed to stdout for another program to parse.

OPTIONS

-n <nsid>
--namespace-id=<nsid>

Retrieve the feature for the given nsid. This is optional and most features do not use this value.

-f <fid>
--feature-id=<fid>

The feature id to send with the command. Value provided should be in hex.

-s <select>
--sel=<select>

Select (SEL): This field specifies which value of the attributes to return in the provided data:

Select

Description

0

Current

1

Default

2

Saved

3

Supported capabilities

4-7

Reserved
-U <uuid-index>
--uuid-index=<uuid-index>

UUID Index of the feature

-l <data-len>
--data-len=<data-len>

The data length for the buffer returned for this feature. Most known features do not use this value. The exception is LBA Range Type

-c <cdw11>
--cdw11=<cdw11>

The value for command dword 11, if applicable.

-b
--raw-binary

Print the raw feature buffer to stdout if the feature returns a structure.

-H
--human-readable

This option will parse and format many of the bit fields into human-readable formats.

-C
--changed

This option will show feature changed.

-o <fmt>
--output-format=<fmt>

Set the reporting format to normal, json or binary. Only one output format can be used at a time.

-v
--verbose

Increase the information detail in the output.

-t <timeout>
--timeout=<timeout>

Override default timeout value. In milliseconds.

EXAMPLES

  • Retrieves the feature for Number of Queues, or feature id 7: 

    # nvme get-feature /dev/nvme0 -f 7

  • The following retrieves the feature for the LBA Range Type, which implicitly requires a buffer and will be printed to the screen in human readable format: 

    # nvme get-feature /dev/nvme0 -f 3

  • Retrieves the feature for the some vendor specific feature and specifically requesting a buffer be allocate for this feature, which will be displayed to the user in as a hex dump: 

    # nvme get-feature /dev/nvme0 -f 0xc0 -l 512

    Get feature with UUID index

# nvme get-feature /dev/nvme0 -f 0xc0 -l 512 -U 0x1

  • The following retrieves the feature for the LBA Range Type, which implicitly requires a buffer and will be saved to a file in its raw format: 

    # nvme get-feature /dev/nvme0 -f 3 --raw-binary > lba_range.raw

    It is probably a bad idea to not redirect stdout when using this mode.

NVME

Part of the nvme-user suite