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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | EXAMPLES | SEE ALSO | AUTHOR | RESOURCES | COPYING | NOTES | COLOPHON |
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TRACE-CMD-RESTORE(1) libtracefs Manual TRACE-CMD-RESTORE(1)
trace-cmd-restore - restore a failed trace record
trace-cmd restore [OPTIONS] [command] cpu-file [cpu-file ...]
The trace-cmd(1) restore command will restore a crashed
trace-cmd-record(1) file. If for some reason a trace-cmd record
fails, it will leave a the per-cpu data files and not create the
final trace.dat file. The trace-cmd restore will append the files
to create a working trace.dat file that can be read with
trace-cmd-report(1).
When trace-cmd record runs, it spawns off a process per CPU and
writes to a per cpu file usually called trace.dat.cpuX, where X
represents the CPU number that it is tracing. If the -o option was
used in the trace-cmd record, then the CPU data files will have
that name instead of the trace.dat name. If a unexpected crash
occurs before the tracing is finished, then the per CPU files will
still exist but there will not be any trace.dat file to read from.
trace-cmd restore will allow you to create a trace.dat file with
the existing data files.
-c
Create a partial trace.dat file from the machine, to be used
with a full trace-cmd restore at another time. This option is
useful for embedded devices. If a server contains the cpu
files of a crashed trace-cmd record (or trace-cmd listen),
trace-cmd restore can be executed on the embedded device with
the -c option to get all the stored information of that
embedded device. Then the file created could be copied to the
server to run the trace-cmd restore there with the cpu files.
If *-o* is not specified, then the file created will be called
'trace-partial.dat'. This is because the file is not a full version
of something that trace-cmd-report(1) could use.
-t tracing_dir
Used with -c, it overrides the location to read the events
from. By default, tracing information is read from the
debugfs/tracing directory. -t will use that location instead.
This can be useful if the trace.dat file to create is from
another machine. Just tar -cvf events.tar debugfs/tracing and
copy and untar that file locally, and use that directory
instead.
-k kallsyms
Used with -c, it overrides where to read the kallsyms file
from. By default, /proc/kallsyms is used. -k will override
the file to read the kallsyms from. This can be useful if the
trace.dat file to create is from another machine. Just copy
the /proc/kallsyms file locally, and use -k to point to that
file.
-o output'
By default, trace-cmd restore will create a trace.dat file (or
trace-partial.dat if -c is specified). You can specify a
different file to write to with the -o option.
-i input
By default, trace-cmd restore will read the information of the
current system to create the initial data stored in the
trace.dat file. If the crash was on another machine, then that
machine should have the trace-cmd restore run with the -c
option to create the trace.dat partial file. Then that file
can be copied to the current machine where trace-cmd restore
will use -i to load that file instead of reading from the
current system.
If a crash happened on another box, you could run:
$ trace-cmd restore -c -o box-partial.dat
Then on the server that has the cpu files:
$ trace-cmd restore -i box-partial.dat trace.dat.cpu0 trace.dat.cpu1
This would create a trace.dat file for the embedded box.
trace-cmd(1), trace-cmd-record(1), trace-cmd-report(1),
trace-cmd-start(1), trace-cmd-stop(1), trace-cmd-extract(1),
trace-cmd-reset(1), trace-cmd-split(1), trace-cmd-list(1),
trace-cmd-listen(1)
Written by Steven Rostedt, <rostedt@goodmis.org[1]>
https://git.kernel.org/pub/scm/utils/trace-cmd/trace-cmd.git/
Copyright (C) 2010 Red Hat, Inc. Free use of this software is
granted under the terms of the GNU Public License (GPL).
1. rostedt@goodmis.org
mailto:rostedt@goodmis.org
This page is part of the trace-cmd (a front-end for Ftrace)
project. Information about the project can be found at
⟨https://www.trace-cmd.org/⟩. If you have a bug report for this
manual page, see ⟨https://www.trace-cmd.org/⟩. This page was
obtained from the project's upstream Git repository
⟨https://git.kernel.org/pub/scm/utils/trace-cmd/trace-cmd.git⟩ on
2025-08-11. (At that time, the date of the most recent commit
that was found in the repository was 2025-08-01.) 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 man-pages@man7.org
libtracefs 09/24/2023 TRACE-CMD-RESTORE(1)
Pages that refer to this page: trace-cmd(1)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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