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

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.

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