lttng-enable-rotation(1) ======================== :revdate: 13 November 2018 NAME ---- lttng-enable-rotation - Set a tracing session's rotation schedule SYNOPSIS -------- [verse] *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 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 a unit suffix). With the option:--size option, the rotation schedule is set 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 without a unit suffix). For both option:--timer and option:--size options, LTTng checks the schedule condition periodically using the monitor timers of the tracing 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 immediate rotation command, man:lttng-rotate(1). You can unset a rotation schedule with the man:lttng-disable-rotation(1) command. See <> for important limitations regarding this command. include::common-cmd-options-head.txt[] Rotation schedule condition ~~~~~~~~~~~~~~~~~~~~~~~~~~~ option:--size='SIZE':: 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 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 a rotation schedule for the tracing session named 'SESSION' instead of the current tracing session. include::common-cmd-help-options.txt[] [[limitations]] LIMITATIONS ----------- The `lttng enable-rotation` command only works when: * The tracing session is created in normal mode or in network streaming mode (see man:lttng-create(1)). * No channel was created with a configured trace file count or size limit (see the nloption:--tracefile-size and nloption:--tracefile-count options in man:lttng-enable-channel(1)). For a given tracing session, LTTng only performs an automatic rotation when no other rotation is currently happening. include::common-cmd-footer.txt[] SEE ALSO -------- man:lttng-rotate(1), man:lttng-disable-rotation(1), man:lttng(1)