NAME

       nbdkit-blkio-plugin - libblkio plugin for NVMe, vhost-user, vDPA, VFIO

SYNOPSIS

        nbdkit blkio [driver=]DRIVER [path=FILENAME] [num-queues=N] ...

DESCRIPTION

       nbdkit-blkio-plugin is an nbdkit(1) plugin for using libblkio to access various disk sources used for
       high performance applications and virtualization.  These include: NVMe, vhost-user, vDPA and VFIO.

       The first parameter after the plugin name should be the libblkio driver.  For example:

        nbdkit blkio virtio-blk-vhost-user path=vhost.sock
                 │              │               │
               plugin         driver       other parameters

   Driver: "nvme-io_uring"
        nbdkit blkio nvme-io_uring path=/dev/ng0n1

       Connect to an NVMe device, issuing commands through Linux io_uring (requires Linux ≥ 5.19).

   Driver: "virtio-blk-vfio-pci"
        nbdkit blkio virtio-blk-vfio-pci path=/sys/bus/pci/devices/0000:00:01.0

       Connect to a PCI device which implements virtio-blk using VFIO.  The path is the path to the device's
       sysfs directory (see lspci(8)).

   Driver: "virtio-blk-vhost-user"
        nbdkit blkio virtio-blk-vhost-user path=vhost.sock

       Connect to a vhost-user block device, such as one exported by qemu-storage-daemon(1).  The path is the
       vhost-user Unix domain socket.  For example:

        qemu-storage-daemon \
           --blockdev driver=file,node-name=file,filename=disk.qcow2 \
           --blockdev driver=qcow2,node-name=qcow2,file=file \
           --export type=vhost-user-blk,id=export,addr.type=unix,addr.path=vhost.sock,node-name=qcow2,writable=on

   Driver: "virtio-blk-vhost-vdpa"
        nbdkit blkio virtio-blk-vhost-vdpa path=chardev

       Connect to a vDPA device which might be implemented in software (eg. VDUSE) or hardware.  The path is the
       vhost-vdpa character device.

   Driver: "io_uring"
        nbdkit blkio io_uring path=FILENAME

       You can use this driver to access local files and block devices through the libblkio "io_uring" driver,
       but it is usually faster and easier to use nbdkit-file-plugin(1).

PARAMETERS

       [driver=]DRIVER
           The name of the libblkio driver to use.

           This parameter is required.

           "driver=" prefix may be omitted in most cases.  See "Magic parameters" in nbdkit(1).

       PROPERTY=VALUE
           Properties  such  as  "path",  "num-entries"  etc are translated to libblkio properties.  Consult the
           libblkio documentation for a complete list.

       get=PROPERTY
           Get (print) the value of a property after connecting.  The property is fetched and printed in  nbdkit
           debug output, so you will need to use the --verbose flag.  This is useful for debugging.

FILES

       $plugindir/nbdkit-blkio-plugin.so
           The plugin.

           Use "nbdkit --dump-config" to find the location of $plugindir.

VERSION

       "nbdkit-blkio-plugin" first appeared in nbdkit 1.34.

SEE ALSO

       nbdkit-file-plugin(1),     lspci(8),     qemu-storage-daemon(1),     https://libblkio.gitlab.io/libblkio,
       https://libblkio.gitlab.io/libblkio/blkio.html.

AUTHORS

       Richard W.M. Jones

COPYRIGHT

       Copyright Red Hat

LICENSE

       Redistribution and use in source and binary forms, with or without modification, are  permitted  provided
       that the following conditions are met:

       •   Redistributions  of  source  code must retain the above copyright notice, this list of conditions and
           the following disclaimer.

       •   Redistributions in binary form must reproduce the above copyright notice, this list of conditions and
           the following disclaimer in the documentation and/or other materials provided with the distribution.

       •   Neither the name of Red Hat nor the names of its contributors may  be  used  to  endorse  or  promote
           products derived from this software without specific prior written permission.

       THIS  SOFTWARE  IS  PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
       INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND  FITNESS  FOR  A  PARTICULAR
       PURPOSE  ARE  DISCLAIMED.  IN  NO EVENT SHALL RED HAT OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
       INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,  PROCUREMENT  OF
       SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
       ON  ANY  THEORY  OF  LIABILITY,  WHETHER  IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
       OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
       DAMAGE.

nbdkit-1.42.4                                      2025-06-16                             nbdkit-blkio-plugin(1)