NAME

       nbdkit-stats-filter - display statistics about operations

SYNOPSIS

        nbdkit --filter=stats PLUGIN statsfile=FILE [statsappend=true]

DESCRIPTION

       "nbdkit-stats-filter" is a filter that displays statistics about NBD operations, such as
       the number of bytes read and written.  Statistics are written to a file once when nbdkit
       exits.

EXAMPLE

       In this example we run guestfish(1) over nbdkit to create an ext4 filesystem on a RAM
       disk, and use the stats filter to display the number of read, write and trim operations
       involved:

        $ nbdkit -U - --filter=stats memory 1G statsfile=/dev/stderr \
                 --run '
              guestfish add-drive "" protocol:nbd server:unix:$unixsocket \
                                     discard:enable format:raw : \
                        run : \
                        mkfs ext4 /dev/sda
        '
        elapsed time: 1.1248 s
        read: 219 ops, 4964864 bytes, 3.53119e+07 bits/s
        write: 78 ops, 34230272 bytes, 2.43458e+08 bits/s
        trim: 33 ops, 1073741824 bytes, 7.63683e+09 bits/s

PARAMETERS

       statsfile=FILE
           The file where we write the stats.

           This parameter is required.

       statsappend=true
           If set then we append to the file instead of replacing it.

FILES

       $filterdir/nbdkit-stats-filter.so
           The filter.

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

VERSION

       "nbdkit-stats-filter" first appeared in nbdkit 1.14.

SEE ALSO

       nbdkit(1), nbdkit-filter(3), nbdkit-log-filter(1).

AUTHORS

       Richard W.M. Jones

COPYRIGHT

       Copyright (C) 2019 Red Hat Inc.

LICENSE

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