Ubuntu Manpage: lttng-rotate - Archive the current trace chunk of an LTTng recording session

Provided by: lttng-tools_2.13.10-1_amd64

NAME

       lttng-rotate - Archive the current trace chunk of an LTTng recording session

SYNOPSIS

       lttng [GENERAL OPTIONS] rotate [--no-wait] [SESSION]

DESCRIPTION

The lttng rotate command archives to the file system the current trace chunk of:

With the SESSION argument
The recording session named SESSION.

Without the SESSION argument
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 rotate command:

• 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 lttng-create(1)).

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.

A rotate-session trigger action can also rotate a recording session (see lttng-add-
trigger(1)).

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).

OPTIONS

       See lttng(1) for GENERAL OPTIONS.

       -n, --no-wait
           Do not ensure that the recording session rotation operation is completed before
           exiting.

   Program information
       -h, --help
           Show help.

           This option attempts to launch /usr/bin/man to view this manual page. Override the
           manual pager path with the LTTNG_MAN_BIN_PATH environment variable.

       --list-options
           List available command options and quit.

EXIT STATUS

       0
           Success

       1
           Command error

       2
           Undefined command

       3
           Fatal error

       4
           Command warning (something went wrong during the command)

ENVIRONMENT

       LTTNG_ABORT_ON_ERROR
           Set to 1 to abort the process after the first error is encountered.

       LTTNG_HOME
           Path to the LTTng home directory.

           Defaults to $HOME.

           Useful when the Unix user running the commands has a non-writable home directory.

       LTTNG_MAN_BIN_PATH
           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 /usr/bin/man.

       LTTNG_SESSION_CONFIG_XSD_PATH
           Path to the directory containing the session.xsd recording session configuration XML
           schema.

       LTTNG_SESSIOND_PATH
           Absolute path to the LTTng session daemon binary (see lttng-sessiond(8)) to spawn from
           the lttng-create(1) command.

           The --sessiond-path general option overrides this environment variable.

FILES

       $LTTNG_HOME/.lttngrc
           Unix user’s LTTng runtime configuration.

           This is where LTTng stores the name of the Unix user’s current recording session
           between executions of lttng(1).  lttng-create(1) and lttng-set-session(1) set the
           current recording session.

       $LTTNG_HOME/lttng-traces
           Default output directory of LTTng traces in local and snapshot modes.

           Override this path with the --output option of the lttng-create(1) command.

       $LTTNG_HOME/.lttng
           Unix user’s LTTng runtime and configuration directory.

       $LTTNG_HOME/.lttng/sessions
           Default directory containing the Unix user’s saved recording session configurations
           (see lttng-save(1) and lttng-load(1)).

       /etc/lttng/sessions
           Directory containing the system-wide saved recording session configurations (see
           lttng-save(1) and lttng-load(1)).

       Note
           $LTTNG_HOME defaults to the value of the HOME environment variable.

EXAMPLES

       Example 1. Rotate the current recording session.

               $ lttng rotate

       Example 2. Rotate a specific recording session.

               $ lttng rotate my-session

       Example 3. Rotate the current recording session without waiting for completion.

           See the --no-wait option.

               $ lttng rotate --no-wait

RESOURCES

       •   LTTng project website <https://lttng.org>

       •   LTTng documentation <https://lttng.org/docs>

       •   LTTng bug tracker <https://bugs.lttng.org>

       •   Git repositories <https://git.lttng.org>

       •   GitHub organization <https://github.com/lttng>

       •   Continuous integration <https://ci.lttng.org/>

       •   Mailing list <https://lists.lttng.org/> for support and development: lttng-
           dev@lists.lttng.org

       •   IRC channel <irc://irc.oftc.net/lttng>: #lttng on irc.oftc.net

COPYRIGHT

       This program is part of the LTTng-tools project.

       LTTng-tools is distributed under the GNU General Public License version 2
       <http://www.gnu.org/licenses/old-licenses/gpl-2.0.en.html>. See the LICENSE
       <https://github.com/lttng/lttng-tools/blob/master/LICENSE> file for details.

THANKS

       Special thanks to Michel Dagenais and the DORSAL laboratory
       <http://www.dorsal.polymtl.ca/> 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.