SYNOPSIS

nvme id-ns <device> [-v | --vendor-specific] [-b | --raw-binary]
                    [--namespace-id=<nsid> | -n <nsid>]

DESCRIPTION

For the NVMe device given, sends an identify namespace command and provides the result and returned structure.

The <device> parameter is mandatory and may be either the NVMe character device (ex: /dev/nvme0), or a namespace block device (ex: /dev/nvme0n1). If the character device is given, the '--namespace-id' option is mandatory, otherwise it will use the ns-id of the namespace for the block device you opened. For block devices, the ns-id used can be overridden with the same option.

On success, the structure may be returned in one of several ways depending on the option flags; the structure may be parsed by the program or the raw buffer may be printed to stdout.

OPTIONS

-n <nsid>
--namespace-id=<nsid>

Retrieve the identify namespace structure for the given nsid. This is required for the character devices, or overrides the block nsid if given.

-b
--raw-binary

Print the raw buffer to stdout. Structure is not parsed by program. This overrides the vendor specific and human readable options.

-v
--vendor-specific

In addition to parsing known fields, this option will dump the vendor specific region of the structure in hex with ascii interpretation.

-H
--human-readable

This option will parse and format many of the bitfields into human-readable formats.

EXAMPLES

  • Has the program interpret the returned buffer and display the known fields in a human readable format:

    # nvme id-ns /dev/nvme0n1
  • If using the character device or overriding namespace id:

    # nvme id-ns /dev/nvme0 -n 1
    # nvme id-ns /dev/nvme0n1 -n 1
    # nvme id-ns /dev/nvme0 --namespace-id=1
  • In addition to showing the known fields, have the program to display the vendor unique field:

    # nvme id-ns /dev/nvme0n1 --vendor-specific
    # nvme id-ns /dev/nvme0n1 -v

    The above will dump the 'vs' buffer in hex since it doesn’t know how to interpret it.

  • Have the program return the raw structure in binary:

    # nvme id-ns /dev/nvme0n1 --raw-binary > id_ns.raw
    # nvme id-ns /dev/nvme0n1 -b > id_ns.raw

    It is probably a bad idea to not redirect stdout when using this mode.

  • Alternatively you may want to send the data to another program that can parse the raw buffer.

    # nvme id-ns /dev/nvme0n1 --raw-binary | nvme_parse_id_ns

    The parse program in the above example can be a program that shows the structure in a way you like. The following program is such an example that will parse it and can accept the output through a pipe, '|', as shown in the above example, or you can 'cat' a saved output buffer to it.

/* File: nvme_parse_id_ns.c */

#include <linux/nvme.h>
#include <stdio.h>
#include <unistd.h>

int main(int argc, char **argv)
{
        unsigned char buf[sizeof(struct nvme_id_ns)];
        struct nvme_id_ns *ns = (struct nvme_id_ns *)buf;

        if (read(STDIN_FILENO, buf, sizeof(buf)))
                return 1;

        printf("nsze : %#llx\n", ns->nsze);
        printf("ncap : %#llx\n", ns->ncap);
        return 0;
}

NVME

Part of the nvme-user suite