lttng-enable-rotation(1)
========================
+:revdate: 13 November 2018
NAME
----
-lttng-enable-rotation - Set a tracing session's automatic rotation schedule
+lttng-enable-rotation - Set a tracing session's rotation schedule
SYNOPSIS
--------
[verse]
-*lttng* ['linkgenoptions:(GENERAL OPTIONS)'] *enable-rotation* (option:--timer='PERIOD' | option:--size='SIZE')
- [option:--session='SESSION']
+*lttng* ['linkgenoptions:(GENERAL OPTIONS)'] *enable-rotation* [option:--session='SESSION']
+ (option:--timer='PERIOD' | option:--size='SIZE' | option:--timer='PERIOD' option:--size='SIZE')
DESCRIPTION
-----------
-The `lttng enable-rotation` command sets an automatic rotation schedule
-for the current tracing session, or for the tracing session named
-'SESSION' if provided. See man:lttng-rotate(1) for more information
-about the concepts of a tracing session _rotation_ and a _trace chunk_.
+The `lttng enable-rotation` command sets a rotation schedule for the
+current tracing session, or for the tracing session named 'SESSION' if
+provided. See man:lttng-rotate(1) for more information about the
+concepts of a tracing session _rotation_ and a _trace chunk_.
With the option:--timer option, the rotation schedule is set so that an
automatic rotation occurs at least every 'PERIOD' (microseconds without
flushed part of the current trace chunk is at least 'SIZE' (bytes
without a unit suffix).
-With both the option:--timer and option:--size options, LTTng checks the
+For both option:--timer and option:--size options, LTTng checks the
schedule condition periodically using the monitor timers of the tracing
-session's channels. This means that, with the option:--timer option, the
-automatic rotation can occur when the elapsed time since the last
-automatic rotation is greater than 'PERIOD', and with the option:--size
-option, the automatic rotation can occur when the size of the flushed
-part of the current trace chunk is greater than 'SIZE'. See the
-nloption:--monitor-timer option in man:lttng-enable-channel(1) for more
-information about the monitor timer.
+session's channels (see the nloption:--monitor-timer option of the
+man:lttng-enable-channel(1) command). This means that:
+
+* With the option:--timer option, the automatic rotation can occur when
+ the elapsed time since the last automatic rotation is slightly greater
+ than 'PERIOD'. The exact precision is governed by the monitor timer's
+ precision, which relies on the precision of the platform's
+ implementation of POSIX timers.
+
+* With the option:--size option, the automatic rotation can occur when
+ the size of the flushed part of the current trace chunk is greater
+ than 'SIZE'.
+
+You can combine the option:--timer and option:--size options.
The naming convention of a trace chunk archive which an automatic
-rotation creates is the same as with the manual rotation command,
+rotation creates is the same as with the immediate rotation command,
man:lttng-rotate(1).
-For a given tracing session, you cannot set multiple automatic rotation
-schedules with the option:--timer or the option:--size option.
-
-You can unset an automatic rotation schedule with the
-man:lttng-disable-rotation(1) command.
+You can unset a rotation schedule with the man:lttng-disable-rotation(1)
+command.
See <<limitations,LIMITATIONS>> for important limitations regarding
this command.
include::common-cmd-options-head.txt[]
-Automatic rotation schedule condition
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-One of:
-
+Rotation schedule condition
+~~~~~~~~~~~~~~~~~~~~~~~~~~~
option:--size='SIZE'::
- Set an automatic rotation schedule so that an automatic rotation
- occurs every time the total size of the flushed part of the current
- trace chunk is at least 'SIZE' bytes. The `k` (kiB), `M` (MiB), and
- `G` (GiB) suffixes are supported.
+ Set a rotation schedule so that an automatic rotation occurs every
+ time the total size of the flushed part of the current trace chunk
+ is at least 'SIZE' bytes. The `k` (kiB), `M` (MiB), and `G` (GiB)
+ suffixes are supported.
option:--timer='PERIOD'::
- Set an automatic rotation schedule so that an automatic rotation
- occurs at least every 'PERIOD' microseconds. The
- `ms` (milliseconds), `s` (seconds), `m` (minutes), and `h` (hours)
- suffixes are supported.
+ Set a rotation schedule so that an automatic rotation occurs at
+ least every 'PERIOD' microseconds. The `ms` (milliseconds), `s`
+ (seconds), `m` (minutes), and `h` (hours) suffixes are supported.
Target
~~~~~~
option:-s 'SESSION', option:--session='SESSION'::
- Set an automatic rotation schedule for the tracing session named
- 'SESSION' instead of the current tracing session.
+ Set a rotation schedule for the tracing session named 'SESSION'
+ instead of the current tracing session.
include::common-cmd-help-options.txt[]