ndctl-enable-namespace - Man Page

enable the given namespace(s)

Synopsis

ndctl enable-namespace <namespace> [<options>]

Theory of Operation

The capacity of an NVDIMM REGION (contiguous span of persistent memory) is accessed via one or more NAMESPACE devices. REGION is the Linux term for what ACPI and UEFI call a DIMM-interleave-set, or a system-physical-address-range that is striped (by the memory controller) across one or more memory modules.

The UEFI specification defines the NVDIMM Label Protocol as the combination of label area access methods and a data format for provisioning one or more NAMESPACE objects from a REGION. Note that label support is optional and if Linux does not detect the label capability it will automatically instantiate a "label-less" namespace per region. Examples of label-less namespaces are the ones created by the kernel’s memmap=ss!nn command line option (see the nvdimm wiki on kernel.org), or NVDIMMs without a valid namespace index in their label area.

Note

Label-less namespaces lack many of the features of their label-rich cousins. For example, their size cannot be modified, or they cannot be fully destroyed (i.e. the space reclaimed). A destroy operation will zero any mode-specific metadata. Finally, for create-namespace operations on label-less namespaces, ndctl bypasses the region capacity availability checks, and always satisfies the request using the full region capacity. The only reconfiguration operation supported on a label-less namespace is changing its mode.

A namespace can be provisioned to operate in one of 4 modes, fsdax, devdax, sector, and raw. Here are the expected usage models for these modes:

Options

<namespace>

A namespaceX.Y device name. The keyword all can be specified to carry out the operation on every namespace in the system, optionally filtered by region (see --region=option)

-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.

-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, --verbose

Emit debug messages for the namespace operation

See Also

ndctl-disable-namespace(1)

Referenced By

ndctl(1), ndctl-check-namespace(1), ndctl-create-namespace(1).

01/26/2021 ndctl 71.1 ndctl Manual