3 nbdkit-stats-filter - display statistics about operations
7 nbdkit --filter=stats PLUGIN statsfile=FILE
8 [statsappend=true] [statsthreshold=PERCENTILE]
12 C<nbdkit-stats-filter> is a filter that displays statistics about NBD
13 operations, such as the number of bytes read and written. Statistics
14 are written to a file once when nbdkit exits.
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
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)
37 other sizes: 3.7% (5 reqs, 3.16 MiB total)
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)
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)
65 flush: 5 ops, 0.000002 s, 0 bytes, 0 bytes/s op, 0 bytes/s total
72 =item B<statsfile=>FILE
74 The file where we write the stats.
76 This parameter is required.
78 =item B<statsappend=true>
80 If set then we append to the file instead of replacing it.
82 =item B<statsthreshold=>PERCENTILE
84 If non-zero, track request size and alignment distribution and print
87 Requests are grouped by the number of bits that are needed to represent
88 the request size (e.g. a request of size 3892 needs will be grouped
89 with all requests of size 2^11=2048 to 2^12-1=4095), and the number of
90 trailing zero bits in the offset.
92 Histogram output is truncated to PERCENTILE of requests. Default: 95.
100 =item F<$filterdir/nbdkit-stats-filter.so>
104 Use C<nbdkit --dump-config> to find the location of C<$filterdir>.
110 C<nbdkit-stats-filter> first appeared in nbdkit 1.14.
116 L<nbdkit-log-filter(1)>.