архивировать текущий фрагмент трассировки сеанса трассировки (Archive a tracing session's current trace chunk)
Имя (Name)
lttng-rotate - Archive a tracing session's current trace chunk
Синопсис (Synopsis)
lttng [GENERAL OPTIONS] rotate [--no-wait] [SESSION]
Описание (Description)
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
lttng-start(1).
• 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:
BEGIN-END-ID
BEGIN
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
END
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
ID
Unique numeric identifier of the trace chunk within its
tracing session.
Trace chunk archive name example:
20171119T152407-0500-20171119T151422-0500-3
Параметры (Options)
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-options
List available command options.
Ограничения (Limitations)
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.
Переменные окружения (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.
Файлы (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)).
Note
$LTTNG_HOME defaults to $HOME when not explicitly set.
Статус выхода (Exit)
0
Success
1
Command error
2
Undefined command
3
Fatal error
4
Command warning (something went wrong during the command)
Ошибки (баги) (Bugs)
If you encounter any issue or usability problem, please report it
on the LTTng bug tracker <https://bugs.lttng.org/projects/lttng-
tools>.
Ресурсы (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
