NAME

       nbdkit-noextents-filter - 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-multi-conn-filter(1), nbdkit-nocache-filter(1), nbdkit-noparallel-filter(1),
       nbdkit-nozero-filter(1), nbdkit-file-plugin(1).

AUTHORS

       Richard W.M. Jones

COPYRIGHT

       Copyright (C) 2019 Red Hat Inc.

LICENSE

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