lttng-save(1) (v2.13)

NAME

lttng-save — Save LTTng recording session configurations

SYNOPSIS

lttng [GENERAL OPTIONS] save [--force] [--output-path=DIR]
      [--all | SESSION]

DESCRIPTION

The lttng save command saves to files the configurations of:

With the SESSION argument

The recording session named SESSION.

Without the SESSION argument

Implicit --all option: all the recording sessions of the connected session daemon for your Unix user, or for all users if your Unix user is root, as listed in the output of lttng list (see lttng-list(1)).

See the “Session daemon connection” section of lttng(1) to learn how a user application connects to a session daemon.

See lttng-concepts(7) to learn more about recording sessions.

Use the save command in conjunction with the lttng-load(1) command to save and restore the complete configurations of recording sessions.

The save command does not save tracing data, only the recording session parameters, including the channel and recording event rule configurations.

The default output directory path is $LTTNG_HOME/.lttng/sessions ($LTTNG_HOME defaults to $HOME). Override the default output directory path with the --output-path option. Each recording session configuration file is named .lttngSNAME, where SNAME is the original recording session name.

By default, the save command does not overwrite existing recording session configuration files: the command fails. Allow the save command to overwrite existing recording session configuration files with the --force option.

See the “EXAMPLES” section below for usage examples.

OPTIONS

See lttng(1) for GENERAL OPTIONS.

-a, --all

Save all the recording session configurations of your Unix user, or of all users if your Unix user is root, as listed in the output of lttng-list(1), instead of the current recording session or the recording session named SESSION.

-f, --force

Overwrite existing recording session configuration files when saving.

-o DIR, --output-path=DIR

Save recording session configuration files to the directory DIR instead of $LTTNG_HOME/.lttng/sessions ($LTTNG_HOME defaults to $HOME).

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:Save all the recording session configurations to the default output directory.

$
lttng save

Example:Save a specific recording session configuration to a specific output directory.

See the --output-path option.

$
lttng save my-session --output-path=/path/to/sessions

Example:Allow LTTng to overwrite existing recording session configuration files when saving.

See the --force option.

$
lttng save --force

RESOURCES

THANKS

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.

SEE ALSO