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  4. nvme-get-feature(1)

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NVME-GET-FEATURE(1) NVMe Manual NVME-GET-FEATURE(1)

NAME

nvme-get-feature - Gets an NVMe feature, returns applicable results

SYNOPSIS

nvme get-feature <device> [--namespace-id=<nsid> | -n <nsid>]


                          [--feature-id=<fid> | -f <fid>] [--cdw11=<cdw11>]


                          [--uuid-index=<uuid-index> | -U <uuid_index>]


                          [--data-len=<data-len> | -l <data-len>]


                          [--sel=<select> | -s <select>]


                          [--raw-binary | -b]


                          [--human-readable | -H]

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

--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.

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

11/11/2021 NVMe