NDCTL-INIT-LABELS(1)             ndctl Manual             NDCTL-INIT-LABELS(1)

NAME
       ndctl-init-labels - initialize the label data area on a dimm or set of
       dimms

SYNOPSIS
       ndctl init-labels <nmem0> [<nmem1>..<nmemN>] [<options>]

DESCRIPTION
       The namespace label area is a small persistent partition of capacity
       available on some NVDIMM devices.  The label area is used to provision
       one, or more, namespaces from regions.  Starting with v4.10 the kernel
       will honor labels for sub-dividing PMEM if all the DIMMs in an
       interleave set / region have a valid namespace index block.

       This command can be used to initialize the namespace index block if it
       is missing or reinitialize it if it is damaged.  Note that
       reinitialization effectively destroys all existing namespace labels on
       the DIMM.

EXAMPLE
       Find the DIMMs that comprise a given region:

           # ndctl list -RD --region=region1
           {
             "dimms":[
               {
                 "dev":"nmem0",
                 "id":"8680-56341200"
               }
             ],
             "regions":[
               {
                 "dev":"region1",
                 "size":268435456,
                 "available_size":0,
                 "type":"pmem",
                 "mappings":[
                   {
                     "dimm":"nmem0",
                     "offset":13958643712,
                     "length":268435456
                   }
                 ]
               }
             ]
           }

       Disable that region so the DIMM label area can be written from
       userspace:

           # ndctl disable-region region1

       Initialize labels:

           # ndctl init-labels nmem0

       Re-enable the region:

           # ndctl enable-region region1

       Create a namespace in that region:

           # ndctl create-namespace --region=region1

OPTIONS
       <memory device(s)>
           A nmemX device name, or a dimm id number. Restrict the operation to
           the specified dimm(s). The keyword all can be specified to indicate
           the lack of any restriction, however this is the same as not
           supplying a --dimm option at all.

       -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=
           A bus id number, or a provider string (e.g. "ACPI.NFIT"). Restrict
           the operation to the specified bus(es). The keyword all can be
           specified to indicate the lack of any restriction, however this is
           the same as not supplying a --bus option at all.

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

       -f, --force
           Force initialization of the label space even if there appears to be
           an existing / valid namespace index.  Warning, this will destroy
           all defined namespaces on the dimm.

       -V, --label-version
           Initialize with a specific version of labels from the namespace
           label specification. Defaults to 1.1

COPYRIGHT
       Copyright (C) 2016 - 2022, 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.

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

ndctl                             2024-01-12              NDCTL-INIT-LABELS(1)