lttng-save

Synopsis

lttng [GENERAL OPTIONS] save [--force] [--output-path=PATH] [SESSION]

Description

The lttng save command saves the configurations of one or more tracing sessions to files.

The lttng save command is used in conjunction with the lttng-load(1) command to save and restore the complete configurations of tracing sessions. This includes the enabled channels and event rules, the context added to channels, the tracing activity, and more. lttng save does not save tracing data, only the tracing session parameters.

If SESSION is omitted, all the existing tracing session configurations are saved (equivalent to using the --all option). Otherwise, SESSION is the name of an existing tracing session. lttng list outputs all the existing tracing sessions (see lttng-list(1)).

The default output directory path is $LTTNG_HOME/.lttng/sessions ($LTTNG_HOME defaults to $HOME). Each tracing session configuration file is named SESSION.lttng, where SESSION is the original tracing session name. The default output directory path can be overridden with the --output-path option.

By default, existing tracing session configuration files are not overwritten when saving; the command fails. The --force option can be used to allow this.

Options

General options are described in lttng(1).

-a, --all

Save all tracing session configurations (default).

-f, --force

Overwrite existing tracing session configuration files when saving.

-o PATH, --output-path=PATH

Set output directory path to PATH.

Environment Variables

LTTNG_ABORT_ON_ERROR

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

LTTNG_HOME

Overrides the $HOME environment variable. Useful when the user running the commands has a non-writable home directory.

LTTNG_MAN_BIN_PATH

Absolute path to the man pager to use for viewing help information about LTTng commands (using lttng-help(1) or lttng COMMAND --help).

LTTNG_SESSION_CONFIG_XSD_PATH

Path in which the session.xsd session configuration XML schema may be found.

LTTNG_SESSIOND_PATH

Full session daemon binary path.

The --sessiond-path option has precedence over this environment variable.

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.

Files

$LTTNG_HOME/.lttngrc

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.

$LTTNG_HOME/lttng-traces

Default output directory of LTTng traces. This can be overridden with the --output option of the lttng-create(1) command.

$LTTNG_HOME/.lttng

User LTTng runtime and configuration directory.

$LTTNG_HOME/.lttng/sessions

Default location of saved user tracing sessions (see lttng-save(1) and lttng-load(1)).

/usr/local/etc/lttng/sessions

System-wide location of saved tracing sessions (see lttng-save(1) and lttng-load(1)).

Exit Status

0

Success

1

Command error

2

Undefined command

3

Fatal error

4

Command warning (something went wrong during the command)

Bugs

If you encounter any issue or usability problem, please report it on the LTTng bug tracker <https://bugs.lttng.org/projects/lttng-tools>.

Resources

• LTTng project website <https://lttng.org>
• LTTng documentation <https://lttng.org/docs>
• Git repositories <http://git.lttng.org>
• GitHub organization <http://github.com/lttng>
• Continuous integration <http://ci.lttng.org/>
• Mailing list <http://lists.lttng.org> for support and development: lttng-dev@lists.lttng.org
• IRC channel <irc://irc.oftc.net/lttng>: #lttng on irc.oftc.net

Copyrights

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.

See Also

lttng-load(1), lttng(1)

Referenced By

lttng(1), lttng-add-context(1), lttng-create(1), lttng-destroy(1), lttng-disable-channel(1), lttng-disable-event(1), lttng-enable-channel(1), lttng-enable-event(1), lttng-help(1), lttng-list(1), lttng-load(1), lttng-metadata(1), lttng-regenerate(1), lttng-sessiond(8), lttng-set-session(1), lttng-snapshot(1), lttng-start(1), lttng-status(1), lttng-stop(1), lttng-track(1), lttng-untrack(1), lttng-version(1), lttng-view(1).