Man1 - ndctl-read-infoblock.1

ndctl-read-infoblock - read and optionally parse the info-block a namespace

  ndctl read-infoblock <namespace0.0> [<namespace1.0>..<namespaceN.Y>] [<options>]

As described in the theory of operation section of ndctl-create-namespace(1), the raw capacity of a namespace may encapsulate a personality, or mode of operation. Specifically, the mode may be set to one of “sector”, “fsdax”, and “devdax”. Each of those modes is defined by an info-block format that uniquely identifies the mode of operation. The read-infoblock command knows the location (relative to the start of the namespace) and field definition of those data structures.

Note that unlike a partition table info-block is not exposed by default, so the namespace needs to be disabled before the info-block can be accessed.

  ndctl disable-namespace namespace0.0
  disabled 1 namespace
  ndctl read-infoblock -j namespace0.0
  [
    {
      "dev":"namespace0.0",
      "signature":"NVDIMM_PFN_INFO",
      "uuid":"56b11990-66b1-4d91-9cac-ca084c051259",
      "parent_uuid":"00000000-0000-0000-0000-000000000000",
      "flags":0,
      "version":"1.3",
      "dataoff":69206016,
      "npfns":1031680,
      "mode":2,
      "start_pad":0,
      "end_trunc":0,
      "align":2097152
    }
  ]

<namespace(s)>

One or more namespaceX.Y device names. The keyword all can be specified to operate on every namespace in the system, optionally filtered by bus id (see –bus= option), or region id (see –region= option).

-V, –verify

Attempt to validate that the info-block is self consistent by validating the embedded checksum, and that info-block formats that contain a parent-uuid attribute also match the base-uuid of the namespace.

-o, –output

Output file

-j, –json

Parse the info-block data into json.

-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).

-r, –region=

A regionX device name, or a region id number. Restrict the operation to the specified region(s). The keyword all can be specified to indicate the lack of any restriction, however this is the same as not supplying a –region option at all.

Copyright © 2016 - 2020, 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.

ndctl-create-namespace(1), UEFI NVDIMM Label Protocol http://www.uefi.org/sites/default/files/resources/UEFI_Spec_2_7.pdf