ndctl−read−labels − read out the label area on a dimm or set of dimms


ndctl read−labels <nmem0> [<nmem1>..<nmemN>] [<options>]


The namespace label area is a small persistent partition of capacity available on some NVDIMM devices. The label area is used to resolve aliasing between pmem and blk capacity by delineating namespace boundaries. This command dumps the raw binary data in a dimm’s label area to stdout or a file. In the multi−dimm case the data is concatenated.


One or more nmemX device names. The keyword all can be specified to operate on every dimm in the system, optionally filtered by bus id (see −−bus= option).

−s, −−size=

Limit the operation to the given number of bytes. A size of 0 indicates to operate over the entire label capacity.

−O, −−offset=

Begin the operation at the given offset into the label area.

−b, −−bus=

Limit operation to memory devices (dimms) that are on the given bus. Where bus can be a provider name or a bus id number.


Turn on verbose debug messages in the library (if ndctl was built with logging and debug enabled).

−I, −−index

Limit the span of the label operation to just the index−block area. This is useful to determine if the dimm label area is initialized. Note that this option and −−size/−−offset are mutually exclusive.

−o, −−output

output file

−j, −−json

parse the label data into json assuming the NVDIMM Namespace Specification format.

−u, −−human

enable json output and convert number formats to human readable strings, for example show the size in terms of "KB", "MB", "GB", etc instead of a signed 64−bit numbers per the JSON interchange format (implies −−json).

Copyright (c) 2016 − 2019, Intel Corporation. License GPLv2: GNU GPL version 2 http://gnu.org/licenses/gpl.html. This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.


UEFI NVDIMM Label Protocol http://www.uefi.org/sites/default/files/resources/UEFI_Spec_2_7.pdf

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