1nbdkit-stats-filter(1)              NBDKIT              nbdkit-stats-filter(1)
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NAME

6       nbdkit-stats-filter - display statistics about operations
7

SYNOPSIS

9        nbdkit --filter=stats PLUGIN statsfile=FILE
10                              [statsappend=true] [statsthreshold=PERCENTILE]
11

DESCRIPTION

13       "nbdkit-stats-filter" is a filter that displays statistics about NBD
14       operations, such as the number of bytes read and written.  Statistics
15       are written to a file once when nbdkit exits.
16

EXAMPLE OUTPUT

18        # nbdkit --filter=exitlast --filter=stats memory 25G statsfile=example.txt
19        # nbd-client localhost /dev/nbd1 && mkfs.ext4 /dev/nbd1 && sync &&
20          nbd-client -d /dev/nbd1
21        [....]
22        # cat example.txt
23        total: 191 ops, 21.917545 s, 25.13 GiB, 1.15 GiB/s
24        read: 136 ops, 0.000230 s, 3.16 MiB, 13.43 GiB/s op, 147.83 KiB/s total
25          Request size and alignment breakdown:
26            12 bits: 68.4% (93 reqs, 372.00 KiB total)
27                 12 bit aligned: 100.0% (93)
28                 13 bit aligned:  72.0% (67)
29                 14 bit aligned:  55.9% (52)
30                 15 bit aligned:  48.4% (45)
31                 16 bit aligned:  43.0% (40)
32            14 bits: 10.3% (14 reqs, 296.00 KiB total)
33                 12 bit aligned: 100.0% (14)
34                 13 bit aligned:  35.7% (5)
35                 19 bit aligned:  21.4% (3)
36        [....]
37            other sizes:  3.7% (5 reqs, 3.16 MiB total)
38
39        write: 36 ops, 0.125460 s, 132.38 MiB, 1.03 GiB/s op, 6.04 MiB/s total
40          Request size and alignment breakdown:
41            12 bits: 50.0% (18 reqs, 72.00 KiB total)
42                 12 bit aligned: 100.0% (18)
43                 13 bit aligned:  77.8% (14)
44                 27 bit aligned:  72.2% (13)
45                 31 bit aligned:  66.7% (12)
46                 32 bit aligned:  33.3% (6)
47                 33 bit aligned:  22.2% (4)
48                 34 bit aligned:  11.1% (2)
49            14 bits: 30.6% (11 reqs, 224.00 KiB total)
50                 12 bit aligned: 100.0% (11)
51                 27 bit aligned:  90.9% (10)
52            25 bits: 11.1% (4 reqs, 128.00 MiB total)
53                 25 bit aligned: 100.0% (4)
54                 26 bit aligned:  50.0% (2)
55                 27 bit aligned:  25.0% (1)
56            16 bits:  2.8% (1 reqs, 64.00 KiB total)
57                 16 bit aligned: 100.0% (1)
58
59        trim: 14 ops, 0.002687 s, 25.00 GiB, 9304.06 GiB/s op, 1.14 GiB/s total
60          Request size and alignment breakdown:
61            31 bits: 85.7% (12 reqs, 24.00 GiB total)
62                 24 bit aligned: 100.0% (12)
63            24 bits:  7.1% (1 reqs, 16.00 MiB total)
64
65        flush: 5 ops, 0.000002 s, 0 bytes, 0 bytes/s op, 0 bytes/s total
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PARAMETERS

68       statsfile=FILE
69           The file where we write the stats.
70
71           This parameter is required.
72
73       statsappend=true
74           If set then we append to the file instead of replacing it.
75
76       statsthreshold=PERCENTILE
77           If non-zero, track request size and alignment distribution and
78           print histogram.
79
80           Requests are grouped by the number of bits that are needed to
81           represent the request size (e.g. a request of size 3892 needs will
82           be grouped with all requests of size 2^11=2048 to 2^12-1=4095), and
83           the number of trailing zero bits in the offset.
84
85           Histogram output is truncated to PERCENTILE of requests. Default:
86           95.
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FILES

89       $filterdir/nbdkit-stats-filter.so
90           The filter.
91
92           Use "nbdkit --dump-config" to find the location of $filterdir.
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VERSION

95       "nbdkit-stats-filter" first appeared in nbdkit 1.14.
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SEE ALSO

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

101       Richard W.M. Jones
102
103       Nikolaus Rath
104
106       Copyright Red Hat
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LICENSE

109       Redistribution and use in source and binary forms, with or without
110       modification, are permitted provided that the following conditions are
111       met:
112
113       •   Redistributions of source code must retain the above copyright
114           notice, this list of conditions and the following disclaimer.
115
116       •   Redistributions in binary form must reproduce the above copyright
117           notice, this list of conditions and the following disclaimer in the
118           documentation and/or other materials provided with the
119           distribution.
120
121       •   Neither the name of Red Hat nor the names of its contributors may
122           be used to endorse or promote products derived from this software
123           without specific prior written permission.
124
125       THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND ANY
126       EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
127       IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
128       PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR CONTRIBUTORS BE
129       LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
130       CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
131       SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
132       BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
133       WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
134       OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
135       ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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139nbdkit-1.36.2                     2023-11-26            nbdkit-stats-filter(1)
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