NVME-WDC-CAP-DIAG(1)              NVMe Manual             NVME-WDC-CAP-DIAG(1)

NAME
       nvme-wdc-cap-diag - Retrieve WDC device's diagnostic log and save to
       file.

SYNOPSIS
       nvme [<global-options>] wdc cap-diag <device>
                               [--output-file=<FILE>, -O <FILE>]
                               [--transfer-size=<SIZE>, -s <SIZE>]

DESCRIPTION
       For the NVMe device given, sends the WDC Vendor Unique
       Capture-Diagnostics request and saves the result to a file.

       The <device> parameter is mandatory NVMe character device (ex:
       /dev/nvme0).

       This will only work on WDC devices supporting this feature. Results for
       any other device are undefined.

OPTIONS
       -O <FILE>, --output-file=<FILE>
           Output file; defaults to device serial number followed by
           "cap_diag" suffix

       -s <SIZE>, --transfer-size=<SIZE>
           Transfer size; defaults to 0x10000 (65536 decimal) bytes

GLOBAL OPTIONS
       The following options are defined at the top-level nvme command and are
       available to this subcommand:

       --dry-run
           Print the command that would be executed, but do not actually
           execute it.

       --no-ioctl-probing
           Disable probing for 64-bit IOCTL support.

       --no-retries
           Disable retry logic on transient errors.

       -o <fmt>, --output-format=<fmt>
           Set the reporting format to normal, tabular, 'json, or binary. Only
           one output format may be used at a time.

       --output-format-version=<version>
           Select the output format version. Version 1 uses the original field
           naming, while version 2 (default) provides more consistent and
           script-friendly field names.

       --timeout=<ms>
           Set the timeout for the command in milliseconds.

       -v, --verbose
           Increase the level of detail in the output. May be specified
           multiple times to further increase verbosity.

       These options can also be set as machine-wide defaults in
       nvme-cli.conf(5). A command-line flag always overrides the file.

EXAMPLES
       o   Gets the capture diagnostics log from the device and saves to
           default file in current directory (e.g. STM00019F3F9cap_diag.bin):

               # nvme wdc cap-diag /dev/nvme0

       o   Gets the capture diagnostics log from the device and saves to
           defined file in current directory (e.g.
           testSTM00019F3F9cap_diag.bin):

               # nvme wdc cap-diag /dev/nvme0 -O test

       o   Gets the capture diagnostics log from the device and saves to
           defined file with pathname (e.g.
           /tmp/testSTM00019F3F9cap_diag.bin):

               # nvme wdc cap-diag /dev/nvme0 -O /tmp/test

       o   Gets the capture diagnostics log from the device transferring the
           data in 64k chunks and saves to default file in current directory
           (e.g. STM00019F3F9internal_fw_log.bin):

               # nvme wdc cap-diag /dev/nvme0 -s 0x10000

       o   Gets the capture diagnostics log from the device transferring the
           data in 16k chunks and saves to default file in current directory
           (e.g. STM00019F3F9internal_fw_log.bin):

               # nvme wdc cap-diag /dev/nvme0 -s 16384

NVME
       Part of the nvme-user suite.

NVMe                              09/18/2026              NVME-WDC-CAP-DIAG(1)