focal (1) nbdkit-error-filter.1.gz

Provided by: nbdkit_1.16.2-1ubuntu3_amd64 bug

NAME
       nbdkit-error-filter - inject errors for testing clients


SYNOPSIS
        nbdkit --filter=error PLUGIN
            [error=EPERM|EIO|ENOMEM|EINVAL|ENOSPC|ESHUTDOWN]
            [error-rate=10%|0.1]
            [error-file=/tmp/inject]
            [error-pread=...] [error-pread-rate=...] [error-pread-file=...]
            [error-pwrite=...] [error-pwrite-rate=...] [error-pwrite-file=...]
            [error-trim=...] [error-trim-rate=...] [error-trim-file=...]
            [error-zero=...] [error-zero-rate=...] [error-zero-file=...]
            [error-extents=...] [error-extents-rate=...] [error-extents-file=...]
            [error-cache=...] [error-cache-rate=...] [error-cache-file=...]


DESCRIPTION
       "nbdkit-error-filter" is an nbdkit filter that injects random errors into replies from the server.  This
       is used for testing that NBD clients can handle errors.

       All parameters are optional, but you should usually specify one of the "error-rate" or "error-*-rate"
       parameters, otherwise this filter will do nothing.


EXAMPLES
       Inject a low rate of errors randomly into the connection:

        nbdkit --filter=error file disk.img error-rate=1%

       Reading, trimming, cache and extents (block status) requests will be successful, but all writes and
       zeroing will return "No space left on device":

        nbdkit --filter=error file disk.img \
                                   error=ENOSPC \
                                   error-pwrite-rate=100% \
                                   error-zero-rate=100%

       To make all connections fail hard 60 seconds after the server is started, use:

        rm -f /tmp/inject
        nbdkit --filter=error file disk.img \
                                   error-rate=100% \
                                   error-file=/tmp/inject
        sleep 60; touch /tmp/inject


PARAMETERS
       error=EPERM|EIO|ENOMEM|EINVAL|ENOSPC|ESHUTDOWN
           When a random error is injected, you can select which one from the range of possible NBD errors (the
           NBD protocol only supports a limited range of error codes).

           This parameter is optional and the default is "EIO" ("Input/output error").

       error-rate=N%
       error-rate=0..1
           The rate of injected errors per NBD request.  This can be expressed as either a percentage between
           "0%" and "100%" or as a probability between 0 and 1.  If "0%" or 0 is used then no errors are ever
           injected, and if "100%" or 1 is used then all requests return errors.

           This parameter is optional and the default is "0%".  Unless you set this, the filter will do nothing.

       error-file=FILENAME
           Errors will only be injected when FILENAME exists.  (Note you must also specify the "error-rate").

           You can use this for fine-grained control over when to inject errors, for example if you want to
           trigger an error at an exact moment during a test, arrange for this file to be created at the
           appropriate time.  Or conversely to test error recovery in a client, create the file initially, and
           then delete it to check the client can recover.

           This parameter is optional.

       error-pread, error-pread-rate, error-pread-file.
           Same as "error", "error-rate" and "error-file" but only apply the settings to NBD pread requests.

       error-pwrite, error-pwrite-rate, error-pwrite-file.
           Same as "error", "error-rate" and "error-file" but only apply the settings to NBD pwrite requests.

       error-trim, error-trim-rate, error-trim-file.
           Same as "error", "error-rate" and "error-file" but only apply the settings to NBD trim requests.

       error-zero, error-zero-rate, error-zero-file.
           Same as "error", "error-rate" and "error-file" but only apply the settings to NBD zero requests.

       error-extents, error-extents-rate, error-extents-file.
           Same as "error", "error-rate" and "error-file" but only apply the settings to NBD block status
           requests to read extents.

       error-cache, error-cache-rate, error-cache-file.
           Same as "error", "error-rate" and "error-file" but only apply the settings to NBD cache requests.


NOTES
   Peculiar debug output
       If you are looking at the debugging output (using "nbdkit -f -v") then you may see peculiar "errors"
       appearing when using this filter, for example:

        nbdkit: file.9: debug: error: pread count=1024 offset=0 flags=0x0

       In fact these are not errors, nbdkit core is simply printing the name of the filter which happens to be
       "error".  When this filter injects an error you will see something like:

        nbdkit: file.4: error: injecting ENOSPC error into pwrite


FILES
       $filterdir/nbdkit-error-filter.so
           The filter.

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


VERSION
       "nbdkit-error-filter" first appeared in nbdkit 1.6.


SEE ALSO
       nbdkit(1), nbdkit-file-plugin(1), nbdkit-full-plugin(1), nbdkit-filter(3).


AUTHORS
       Richard W.M. Jones


       Copyright (C) 2018 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.

       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,
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       SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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