NAME¶

nbdkit-rotational-filter - set if a plugin is rotational or not

SYNOPSIS¶

 nbdkit --filter=rotational PLUGIN [rotational=true|false]

DESCRIPTION¶

"nbdkit-rotational-filter" is a filter for nbdkit(1) which lets you change the rotational property of a plugin.

The rotational property is a boolean flag which hints to the client whether the plugin behaves like a spinning disk (if rotational is true) or like a solid state disk or RAM (if rotational is false). If a disk is rotational, then the client may attempt to schedule disk accesses to reduce seek times using the elevator algorithm (https://en.wikipedia.org/wiki/Elevator_algorithm).

Adding this filter without using the "rotational" parameter forces the plugin to advertise that it is rotational. You can explicitly set the rotational property by using "rotational=true" or "rotational=false".

PARAMETERS¶

rotational=true

Set the rotational property, indicating that the plugin behaves like a spinning disk. This is the default when you enable this filter.

rotational=false

Clear the rotational property, indicating that the plugin behaves like a solid state disk or RAM.

FILES¶

$filterdir/nbdkit-rotational-filter.so

The filter.

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

VERSION¶

"nbdkit-rotational-filter" first appeared in nbdkit 1.40.

SEE ALSO¶

nbdkit(1), nbdkit-file-plugin(1), nbdkit-readonly-filter(1), nbdkit-spinning-filter(1), nbdinfo(1), nbdkit-filter(3), https://en.wikipedia.org/wiki/Elevator_algorithm.

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.