lttng-rotate(1) — Linux manual page


LTTNG-ROTATE(1)               LTTng Manual               LTTNG-ROTATE(1)

NAME         top

       lttng-rotate - Archive a tracing session's current trace chunk

SYNOPSIS         top

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

DESCRIPTION         top

       The lttng rotate command archives the current trace chunk of the
       current tracing session, or of the tracing session named SESSION
       if provided, to the file system. This action is called a tracing
       session rotation.

       Once a trace chunk is archived, LTTng does not manage it anymore:
       you can read it, modify it, move it, or remove it.

       An archived trace chunk is a collection of metadata and data
       stream files which form a self-contained trace.

       The current trace chunk of a given tracing session includes:

       •   The stream files already written to the file system, and
           which are not part of a previously archived trace chunk,
           since the most recent event amongst:

           •   The first time the tracing session was started with

           •   The last rotation, either an immediate one with lttng
               rotate, or an automatic one from a rotation schedule
               previously set with lttng-enable-rotation(1).

       •   The content of all the non-flushed sub-buffers of the tracing
           session’s channels.

       You can use lttng rotate either at any time when the tracing
       session is active (see lttng-start(1)), or a single time once the
       tracing session becomes inactive (see lttng-stop(1)).

       By default, the lttng rotate command ensures that the rotation is
       done before printing the archived trace chunk’s path and
       returning to the prompt. The printed path is absolute when the
       tracing session was created in normal mode and relative to the
       relay daemon’s output directory (see the --output option in
       lttng-relayd(8)) when it was created in network streaming mode
       (see lttng-create(1)).

       With the --no-wait option, the command finishes immediately,
       hence a rotation might not be completed when the command is done.
       In this case, there is no easy way to know when the current trace
       chunk is archived, and the command does not print the archived
       trace chunk’s path.

       Because a rotation causes the tracing session’s current
       sub-buffers to be flushed, 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.

       See LIMITATIONS for important limitations regarding this command.

   Trace chunk archive naming
       A trace chunk archive is a subdirectory of a tracing session’s
       output directory (see the --output option in lttng-create(1))
       which contains, through tracing domain and possibly UID/PID
       subdirectories, metadata and data stream files.

       A trace chunk archive is, at the same time:

       •   A self-contained LTTng trace.

       •   A member of a set of trace chunk archives which form the
           complete trace of a tracing session.

       In other words, an LTTng trace reader can read both the tracing
       session output directory (all the trace chunk archives), or a
       single trace chunk archive.

       When a tracing session rotation occurs, the created trace chunk
       archive is named:


           Date and time of the beginning of the trace chunk archive
           with the ISO 8601-compatible YYYYmmddTHHMMSS±HHMM form, where
           YYYYmmdd is the date and HHMMSS±HHMM is the time with the
           time zone offset from UTC.

           Example: 20171119T152407-0500

           Date and time of the end of the trace chunk archive with the
           ISO 8601-compatible YYYYmmddTHHMMSS±HHMM form, where YYYYmmdd
           is the date and HHMMSS±HHMM is the time with the time zone
           offset from UTC.

           Example: 20180118T152407+0930

           Unique numeric identifier of the trace chunk within its
           tracing session.

       Trace chunk archive name example:

OPTIONS         top

       General options are described in lttng(1).

       -n, --no-wait
           Do not ensure that the rotation is done before returning to
           the prompt.

   Program information
       -h, --help
           Show command help.

           This option, like lttng-help(1), attempts to launch
           /usr/bin/man to view the command’s man page. The path to the
           man pager can be overridden by the LTTNG_MAN_BIN_PATH
           environment variable.

           List available command options.

LIMITATIONS         top

       The lttng rotate command only works when:

       •   The tracing session is 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 in lttng-enable-channel(1)).

       •   No immediate rotation (lttng rotate) is currently happening.


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

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

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

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

           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         top

           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.

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

           User LTTng runtime and configuration directory.

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

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

           $LTTNG_HOME defaults to $HOME when not explicitly set.

EXIT STATUS         top


           Command error

           Undefined command

           Fatal error

           Command warning (something went wrong during the command)

BUGS         top

       If you encounter any issue or usability problem, please report it
       on the LTTng bug tracker <

RESOURCES         top

       •   LTTng project website <>

       •   LTTng documentation <>

       •   Git repositories <>

       •   GitHub organization <>

       •   Continuous integration <>

       •   Mailing list <> for support and

       •   IRC channel <irc://>: #lttng on

COPYRIGHTS         top

       This program is part of the LTTng-tools project.

       LTTng-tools is distributed under the GNU General Public License
       version 2 <
       licenses/gpl-2.0.en.html>. See the LICENSE
       <> file
       for details.

THANKS         top

       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.

AUTHORS         top

       LTTng-tools was originally written by Mathieu Desnoyers, Julien
       Desfossez, and David Goulet. More people have since contributed
       to it.

       LTTng-tools is currently maintained by Jérémie Galarneau

SEE ALSO         top

       lttng-enable-rotation(1), lttng-disable-rotation(1), lttng(1)

COLOPHON         top

       This page is part of the LTTng-Tools (    LTTng tools) project.
       Information about the project can be found at 
       ⟨⟩.  It is not known how to report bugs for this
       man page; if you know, please send a mail to
       This page was obtained from the project's upstream Git repository
       ⟨git://⟩ on 2019-11-19.  (At that
       time, the date of the most recent commit that was found in the
       repository was 2019-11-14.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there
       is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to

LTTng 2.12.0-pre               10/29/2018                LTTNG-ROTATE(1)

Pages that refer to this page: lttng(1)lttng-destroy(1)lttng-enable-channel(1)lttng-enable-rotation(1)lttng-regenerate(1)lttng-stop(1)babeltrace2-source.ctf.fs(7)