nbdkit-noextents-filter - Man Page

disable extents in the underlying plugin

Synopsis

 nbdkit --filter=noextents plugin

Description

“Extents” are a feature of the NBD protocol / nbdkit which allow the client to detect sparse regions of the underlying disk. nbdkit-noextents-filter disables this so that the plugin appears to be fully allocated, at least to a client that requests structured replies.  It is also possible to use the --no-sr option to nbdkit to prevent the client from using structured replies, which among its other side effects will prevent the client from querying extents at all.

This filter can be useful when combined with nbdkit-file-plugin(1) serving a file from a file system known to have poor lseek(2) performance (tmpfs is known to be one such system).

Parameters

There are no parameters specific to nbdkit-noextents-filter.  Any parameters are passed through to and processed by the underlying plugin in the normal way.

Files

$filterdir/nbdkit-noextents-filter.so

The filter.

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

Version

nbdkit-noextents-filter first appeared in nbdkit 1.14.

See Also

nbdkit(1), nbdkit-filter(3), nbdkit-extentlist-filter(1), nbdkit-fua-filter(1), nbdkit-nocache-filter(1), nbdkit-noparallel-filter(1), nbdkit-nozero-filter(1), nbdkit-file-plugin(1).

Authors

Richard W.M. Jones

License

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

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.

Referenced By

nbdkit(1), nbdkit-extentlist-filter(1), nbdkit-file-plugin(1), nbdkit-filter(3), nbdkit-fua-filter(1), nbdkit-nocache-filter(1), nbdkit-noparallel-filter(1), nbdkit-nozero-filter(1), nbdkit-release-notes-1.12(1).

2020-03-31 nbdkit-1.19.6 NBDKIT