e8970cd97b64187eac8b3ad8647bfd8d2073477c
[lttng-tools.git] / doc / man / lttng-enable-rotation.1.txt
1 lttng-enable-rotation(1)
2 ========================
3
4
5 NAME
6 ----
7 lttng-enable-rotation - Set a tracing session's rotation schedule
8
9
10 SYNOPSIS
11 --------
12 [verse]
13 *lttng* ['linkgenoptions:(GENERAL OPTIONS)'] *enable-rotation* [option:--session='SESSION']
14 (option:--timer='PERIOD' | option:--size='SIZE' | option:--timer='PERIOD' option:--size='SIZE')
15
16
17 DESCRIPTION
18 -----------
19 The `lttng enable-rotation` command sets a rotation schedule for the
20 current tracing session, or for the tracing session named 'SESSION' if
21 provided. See man:lttng-rotate(1) for more information about the
22 concepts of a tracing session _rotation_ and a _trace chunk_.
23
24 With the option:--timer option, the rotation schedule is set so that an
25 automatic rotation occurs at least every 'PERIOD' (microseconds without
26 a unit suffix).
27
28 With the option:--size option, the rotation schedule is set
29 so that an automatic rotation occurs every time the total size of the
30 flushed part of the current trace chunk is at least 'SIZE' (bytes
31 without a unit suffix).
32
33 For both option:--timer and option:--size options, LTTng checks the
34 schedule condition periodically using the monitor timers of the tracing
35 session's channels (see the nloption:--monitor-timer option of the
36 man:lttng-enable-channel(1) command). This means that:
37
38 * With the option:--timer option, the automatic rotation can occur when
39 the elapsed time since the last automatic rotation is slightly greater
40 than 'PERIOD'. The exact precision is governed by the monitor timer's
41 precision, which relies on the precision of the platform's
42 implementation of POSIX timers.
43
44 * With the option:--size option, the automatic rotation can occur when
45 the size of the flushed part of the current trace chunk is greater
46 than 'SIZE'.
47
48 You can combine the option:--timer and option:--size options.
49
50 The naming convention of a trace chunk archive which an automatic
51 rotation creates is the same as with the immediate rotation command,
52 man:lttng-rotate(1).
53
54 You can unset a rotation schedule with the man:lttng-disable-rotation(1)
55 command.
56
57 See <<limitations,LIMITATIONS>> for important limitations regarding
58 this command.
59
60
61 include::common-cmd-options-head.txt[]
62
63
64 Rotation schedule condition
65 ~~~~~~~~~~~~~~~~~~~~~~~~~~~
66 option:--size='SIZE'::
67 Set a rotation schedule so that an automatic rotation occurs every
68 time the total size of the flushed part of the current trace chunk
69 is at least 'SIZE' bytes. The `k` (kiB), `M` (MiB), and `G` (GiB)
70 suffixes are supported.
71
72 option:--timer='PERIOD'::
73 Set a rotation schedule so that an automatic rotation occurs at
74 least every 'PERIOD' microseconds. The `ms` (milliseconds), `s`
75 (seconds), `m` (minutes), and `h` (hours) suffixes are supported.
76
77
78 Target
79 ~~~~~~
80 option:-s 'SESSION', option:--session='SESSION'::
81 Set a rotation schedule for the tracing session named 'SESSION'
82 instead of the current tracing session.
83
84
85 include::common-cmd-help-options.txt[]
86
87
88 [[limitations]]
89 LIMITATIONS
90 -----------
91 The `lttng enable-rotation` command only works when:
92
93 * The tracing session is created in normal mode or in network streaming
94 mode (see man:lttng-create(1)).
95
96 * No channel was created with a configured trace file count or size
97 limit (see the nloption:--tracefile-size and
98 nloption:--tracefile-count options in man:lttng-enable-channel(1)).
99
100 For a given tracing session, LTTng only performs an automatic rotation
101 when no other rotation is currently happening.
102
103
104 include::common-cmd-footer.txt[]
105
106
107 SEE ALSO
108 --------
109 man:lttng-rotate(1),
110 man:lttng-disable-rotation(1),
111 man:lttng(1)
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