lttng-enable-rotation — Set a tracing session's rotation schedule
lttng enable-rotation command sets a rotation schedule for the
current tracing session, or for the tracing session named SESSION if
provided. See lttng-rotate(1) for more information about the
concepts of a tracing session rotation and a trace chunk.
--timer option, the rotation schedule is set so that an
automatic rotation occurs at least every PERIOD (microseconds without
a unit suffix).
--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).
--size options, LTTng checks the
schedule condition periodically using the monitor timers of the tracing
session’s channels (see the
--monitor-timer option of the
lttng-enable-channel(1) command). This means that:
--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.
--size option, the automatic rotation can occur when
the size of the flushed part of the current trace chunk is greater
The naming convention of a trace chunk archive which an automatic rotation creates is the same as with the immediate rotation command, lttng-rotate(1).
You can unset a rotation schedule with the lttng-disable-rotation(1) command.
See LIMITATIONS for important limitations regarding this command.
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
M (MiB), and
suffixes are supported.
Set a rotation schedule so that an automatic rotation occurs at
least every PERIOD microseconds. The
m (minutes), and
h (hours) suffixes are supported.
lttng enable-rotation command only works when:
The tracing session is created in normal mode or in network streaming mode (see lttng-create(1)).
No channel was created with a configured trace file count or size
limit (see the
--tracefile-count options in lttng-enable-channel(1)).
For a given tracing session, LTTng only performs an automatic rotation when no other rotation is currently happening.
Set to 1 to abort the process after the first error is encountered.
$HOME environment variable. Useful when the user
running the commands has a non-writable home directory.
Absolute path to the man pager to use for viewing help information
about LTTng commands (using lttng-help(1) or
lttng COMMAND --help).
Path in which the
session.xsd session configuration XML
schema may be found.
Full session daemon binary path.
--sessiond-path option has precedence over this
Note that the lttng-create(1) command can spawn an LTTng session daemon automatically if none is running. See lttng-sessiond(8) for the environment variables influencing the execution of the session daemon.
User LTTng runtime configuration.
This is where the per-user current tracing session is stored between executions of lttng(1). The current tracing session can be set with lttng-set-session(1). See lttng-create(1) for more information about tracing sessions.
Default output directory of LTTng traces. This can be overridden
--output option of the lttng-create(1)
User LTTng runtime and configuration directory.
$LTTNG_HOME defaults to
$HOME when not explicitly set.
Command warning (something went wrong during the command)
If you encounter any issue or usability problem, please report it on the LTTng bug tracker.
Special thanks to Michel Dagenais and the DORSAL laboratory at École Polytechnique de Montréal for the LTTng journey.
Also thanks to the Ericsson teams working on tracing which helped us greatly with detailed bug reports and unusual test cases.