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

Provided by: nbdkit_1.42.0-1ubuntu1_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|1:10]
            [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.

       nbdkit-evil-filter(1) is a related filter that injects data corruption instead of errors.
       nbdkit-readonly-filter(1) is another filter which can change a plugin from read-write to read-only (and
       vice versa).


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%

       (see also nbdkit-readonly-filter(1)).

       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
       error-rate=N:M
           The rate of injected errors per NBD request.  This can be expressed as a percentage between "0%" and
           "100%", or as a probability between 0 and 1, or as a ratio like "1:10".  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.
           (nbdkit ≥ 1.12)

           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.
           (nbdkit ≥ 1.14)

           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") references to the name of this filter
       show up as "error-inject:", and such lines indicate that the filter is not altering output, for example:

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

       Conversely, references to the string "error:" occur when the nbdkit_error(3) API was used, including when
       this filter injects an error, as in:

        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-evil-filter(1), nbdkit-file-plugin(1), nbdkit-full-plugin(1),
       nbdkit-readonly-filter(1), nbdkit-retry-filter(1), nbdkit-retry-request-filter(1), nbdkit-filter(3).


AUTHORS
       Richard W.M. Jones


       Copyright Red Hat


LICENSE
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       •   Neither the name of Red Hat nor the names of its contributors may be used to endorse or promote
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