1NDCTL-DESTROY-NAMESPACE(1)       ndctl Manual       NDCTL-DESTROY-NAMESPACE(1)
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NAME

6       ndctl-destroy-namespace - destroy the given namespace(s)
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SYNOPSIS

9       ndctl destroy-namespace <namespace> [<options>]
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THEORY OF OPERATION

12       The capacity of an NVDIMM REGION (contiguous span of persistent memory)
13       is accessed via one or more NAMESPACE devices. REGION is the Linux term
14       for what ACPI and UEFI call a DIMM-interleave-set, or a
15       system-physical-address-range that is striped (by the memory
16       controller) across one or more memory modules.
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18       The UEFI specification defines the NVDIMM Label Protocol as the
19       combination of label area access methods and a data format for
20       provisioning one or more NAMESPACE objects from a REGION. Note that
21       label support is optional and if Linux does not detect the label
22       capability it will automatically instantiate a "label-less" namespace
23       per region. Examples of label-less namespaces are the ones created by
24       the kernel’s memmap=ss!nn command line option (see the nvdimm wiki on
25       kernel.org), or NVDIMMs without a valid namespace index in their label
26       area.
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28       A namespace can be provisioned to operate in one of 4 modes, fsdax,
29       devdax, sector, and raw. Here are the expected usage models for these
30       modes:
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32       ·   fsdax: Filesystem-DAX mode is the default mode of a namespace when
33           specifying ndctl create-namespace with no options. It creates a
34           block device (/dev/pmemX[.Y]) that supports the DAX capabilities of
35           Linux filesystems (xfs and ext4 to date). DAX removes the page
36           cache from the I/O path and allows mmap(2) to establish direct
37           mappings to persistent memory media. The DAX capability enables
38           workloads / working-sets that would exceed the capacity of the page
39           cache to scale up to the capacity of persistent memory. Workloads
40           that fit in page cache or perform bulk data transfers may not see
41           benefit from DAX. When in doubt, pick this mode.
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43       ·   devdax: Device-DAX mode enables similar mmap(2) DAX mapping
44           capabilities as Filesystem-DAX. However, instead of a block-device
45           that can support a DAX-enabled filesystem, this mode emits a single
46           character device file (/dev/daxX.Y). Use this mode to assign
47           persistent memory to a virtual-machine, register persistent memory
48           for RDMA, or when gigantic mappings are needed.
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50       ·   sector: Use this mode to host legacy filesystems that do not
51           checksum metadata or applications that are not prepared for torn
52           sectors after a crash. Expected usage for this mode is for small
53           boot volumes. This mode is compatible with other operating systems.
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55       ·   raw: Raw mode is effectively just a memory disk that does not
56           support DAX. Typically this indicates a namespace that was created
57           by tooling or another operating system that did not know how to
58           create a Linux fsdax or devdax mode namespace. This mode is
59           compatible with other operating systems, but again, does not
60           support DAX operation.
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OPTIONS

63       <namespace>
64           A namespaceX.Y device name. The keyword all can be specified to
65           carry out the operation on every namespace in the system,
66           optionally filtered by region (see --region=option)
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68       -r, --region=
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70               A 'regionX' device name, or a region id number. The keyword 'all' can
71               be specified to carry out the operation on every region in the system,
72               optionally filtered by bus id (see --bus= option).
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74       -b, --bus=
75           Enforce that the operation only be carried on devices that are
76           attached to the given bus. Where bus can be a provider name or a
77           bus id number.
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79       -v, --verbose
80           Emit debug messages for the namespace operation
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82       -f, --force
83           Unless this option is specified the destroy namespace operation
84           will fail if the namespace is presently active. Specifying --force
85           causes the namespace to be disabled before the operation is
86           attempted. However, if the namespace is mounted then the disable
87           namespace and destroy namespace operations will be aborted. The
88           namespace must be unmounted before being destroyed.
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91       Copyright (c) 2016 - 2019, Intel Corporation. License GPLv2: GNU GPL
92       version  2  <http://gnu.org/licenses/gpl.html>.  This is free software:
93       you are free to change and redistribute it. There is  NO  WARRANTY,  to
94       the extent permitted by law.
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SEE ALSO

97       ndctl-create-namespace(1)
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101ndctl                             2019-05-10        NDCTL-DESTROY-NAMESPACE(1)
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