lttng-rotate — Archive the current trace chunk of an LTTng recording session
lttng rotate command archives to the file system
the current trace chunk of:
The recording session named
The current recording session (see lttng-concepts(7) to learn more about the current recording session).
This action is called a recording session rotation.
See lttng-concepts(7) to learn more about the recording session rotation and trace chunk concepts.
You can use the
Any time the recording session is active.
A single time once the recording session becomes inactive.
See lttng-concepts(7) to learn more about the activity of a recording session.
By default, the
rotate command ensures that LTTng finished performing
the recording session rotation before it prints the path of the archived
trace chunk and exits. The printed path is absolute when the recording
session was created in normal mode and relative to the base output
directory of the relay daemon (see the
--output option of
lttng-relayd(8)) when it was created in network streaming mode (see
Make the command exit immediately with the
--no-wait option. In
this case, there’s no easy way to know when the current trace chunk
becomes archived, and the command does not print the path of the
archived trace chunk.
Because LTTng flushes the current sub-buffers of the selected recording session when it performs a recording session rotation, archived trace chunks are never redundant, that is, they do not overlap over time like snapshots can (see lttng-snapshot(1)). Also, a rotation does not directly cause discarded event records or packets.
rotate-session trigger action can also rotate a recording session
See the “EXAMPLES” section below for usage examples.
Important:You may only use the
rotate command when:
The selected recording session was created in normal mode or in network streaming mode (see lttng-create(1)).
LTTng is not currently performing an immediate rotation (this command).
Command warning (something went wrong during the command)
1 to abort the process after the first error is
Path to the LTTng home directory.
Useful when the Unix user running the commands has a non-writable home directory.
Absolute path to the manual pager to use to read the LTTng
command-line help (with lttng-help(1) or with the
--help option) instead of
Path to the directory containing the
session.xsd recording session
configuration XML schema.
--sessiond-path general option overrides this environment
Unix user’s LTTng runtime configuration.
Default output directory of LTTng traces in local and snapshot modes.
Override this path with the
--output option of the
Unix user’s LTTng runtime and configuration directory.
$LTTNG_HOME defaults to the value of the
Example:Rotate the current recording session.
Example:Rotate a specific recording session.
lttng rotate my-session
Example:Rotate the current recording session without waiting for completion.
lttng rotate --no-wait
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.