SYNOPSIS

nvme [<global-options>] feat volatile-wc <device>
                        [--wce | -w]
                        [--sel=<select> | -S <select>] [--save | -s]

DESCRIPTION

Get and set volatile write cache feature.

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 setting option (--wce) is specified, the command will update the volatile write cache configuration. If the option is omitted, it will retrieve and display the current configuration.

On success it returns 0, error code otherwise.

OPTIONS

-w
--wce

Write Cache Enable. If specified, enables the volatile write cache. If omitted when updating, disables the volatile write cache.

-S <select>
--sel=<select>

Select (SEL): This field specifies which value of the attributes to return in the provided data:

-s
--save

Save the attribute so that it persists through all power states and resets.

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

  • Has the program issue a feat volatile-wc to get the current configuration: 

    # nvme feat volatile-wc /dev/nvme0

  • Has the program issue a feat volatile-wc to enable the volatile write cache: 

    # nvme feat volatile-wc /dev/nvme0 --wce --save

NVME

Part of the nvme-user suite.