Ubuntu Manpage: lttng-enable-rotation - Set an LTTng recording session rotation schedule

NAME

       lttng-enable-rotation - Set an LTTng recording session rotation schedule

SYNOPSIS

       lttng [GENERAL OPTIONS] enable-rotation [--session=SESSION]
             (--timer=PERIODUS | --size=SIZE | --timer=PERIODUS --size=SIZE)

DESCRIPTION

The lttng enable-rotation command sets a recording session rotation schedule for:

With the --session=SESSION option
The recording session named SESSION.

Without the --session option
The current recording session (see lttng-concepts(7) to learn more about the current
recording session).

See lttng-concepts(7) to learn more about the recording session rotation and trace chunk
concepts.

With the --timer=PERIODUS option, the enable-rotation command sets a rotation schedule so
that LTTng performs an automatic rotation at least every PERIODUS.

With the --size=SIZE option, the enable-rotation command sets a rotation schedule so that
LTTng performs an automatic rotation every time the total size of the flushed part of the
current trace chunk is at least SIZE.

For both the --timer and --size options, LTTng checks the schedule condition periodically
using the monitor timers of the channels of the selected recording session (see the
--monitor-timer option of the lttng-enable-channel(1) command). This means that:

• With the --timer=PERIODUS option, LTTng can perform an automatic rotation when the
elapsed time since the last automatic rotation is slightly greater than PERIODUS.

The exact precision depends on the precision of the monitor timer, which relies on the
precision of the platform implementation of POSIX timers.

• With the --size=SIZE option, LTTng can perform an automatic rotation when the size of
the flushed part of the current trace chunk is greater than SIZE.

You may combine the --timer and --size options.

See the lttng-concepts(7) to learn how LTTng names a trace chunk archive directory.

See the “EXAMPLES” section below for usage examples.

Unset a recording session rotation schedule with the lttng-disable-rotation(1) command.

Important
You may only use the enable-rotation command when:

• The selected recording session was 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-size and --tracefile-count options of the lttng-enable-channel(1)
command).

For a given recording session, LTTng only performs an automatic rotation when it’s not
currently performing a rotation.

OPTIONS

       See lttng(1) for GENERAL OPTIONS.

   Rotation schedule condition
       --size=SIZE
           Set a rotation schedule so that LTTng performs an automatic rotation every time the
           total size of the flushed part of the current trace chunk is at least SIZE bytes.

           The k (KiB), M (MiB), and G (GiB) suffixes are supported.

       --timer=PERIODUS
           Set a rotation schedule so that LTTng performs an automatic rotation approximately
           every PERIODUS microseconds.

           The ms (milliseconds), s (seconds), m (minutes), and h (hours) suffixes are supported.

   Recording target
       -s SESSION, --session=SESSION
           Set a rotation schedule for the recording session named SESSION instead of the current
           recording session.

   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. Set the size-based rotation schedule of the current recording session.

           See the --size option.

               $ lttng disable-rotation --size=256M

       Example 2. Set the periodic rotation schedule of a specific recording session.

           See the --timer and --session options.

               $ lttng disable-rotation --session=my-session --timer=5m

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.