$
lttng rotate
lttng-rotate — Archive the current trace chunk of an LTTng recording session
lttng [GENERAL OPTIONS] rotate [--no-wait
] [SESSION
]
The lttng rotate
command archives to the file system
the current trace chunk of:
SESSION
argument
The recording session named SESSION
.
SESSION
argument
The current recording session (see lttng-concepts(7) to learn more about the current recording session).
This action is called a recording session rotation.
See lttng-concepts(7) to learn more about the recording session rotation and trace chunk concepts.
You can use the rotate
command:
Any time the recording session is active.
A single time once the recording session becomes inactive.
See lttng-concepts(7) to learn more about the activity of a recording session.
By default, the rotate
command ensures that LTTng finished performing
the recording session rotation before it prints the path of the archived
trace chunk and exits. The printed path is absolute when the recording
session was created in normal mode and relative to the base output
directory of the relay daemon (see the --output
option of
lttng-relayd(8)) when it was created in network streaming mode (see
lttng-create(1)).
Make the command exit immediately with the --no-wait
option. In
this case, there’s no easy way to know when the current trace chunk
becomes archived, and the command does not print the path of the
archived trace chunk.
Because LTTng flushes the current sub-buffers of the selected recording session when it performs a recording session rotation, 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.
A rotate-session
trigger action can also rotate a recording session
(see lttng-add-trigger(1)).
See the “EXAMPLES” section below for usage examples.
Important:You may only use the rotate
command when:
The selected recording session was created in normal mode or in network streaming mode (see lttng-create(1)).
LTTng is not currently performing an immediate rotation (this command).
See lttng(1) for GENERAL OPTIONS.
-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.
Success
Command error
Undefined command
Fatal error
Command warning (something went wrong during the command)
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.
$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.
Example:Rotate the current recording session.
$
lttng rotate
Example:Rotate a specific recording session.
$
lttng rotate my-session
Example:Rotate the current recording session without waiting for completion.
See the --no-wait
option.
$
lttng rotate --no-wait
Mailing list for support and
development: lttng-dev@lists.lttng.org
IRC channel: #lttng
on irc.oftc.net
This program is part of the LTTng-tools project.
LTTng-tools is distributed under the
GNU General
Public License version 2. See the
LICENSE
file
for details.
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.