1TRACE-CMD-RESTORE(1) libtracefs Manual TRACE-CMD-RESTORE(1)
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6 trace-cmd-restore - restore a failed trace record
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9 trace-cmd restore [OPTIONS] [command] cpu-file [cpu-file ...]
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12 The trace-cmd(1) restore command will restore a crashed
13 trace-cmd-record(1) file. If for some reason a trace-cmd record fails,
14 it will leave a the per-cpu data files and not create the final
15 trace.dat file. The trace-cmd restore will append the files to create a
16 working trace.dat file that can be read with trace-cmd-report(1).
17 When trace-cmd record runs, it spawns off a process per CPU and writes
19 to a per cpu file usually called trace.dat.cpuX, where X represents the
20 CPU number that it is tracing. If the -o option was used in the
21 trace-cmd record, then the CPU data files will have that name instead
22 of the trace.dat name. If a unexpected crash occurs before the tracing
23 is finished, then the per CPU files will still exist but there will not
24 be any trace.dat file to read from. trace-cmd restore will allow you to
25 create a trace.dat file with the existing data files.
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28 -c
29 Create a partial trace.dat file from the machine, to be used with a
30 full trace-cmd restore at another time. This option is useful for
31 embedded devices. If a server contains the cpu files of a crashed
32 trace-cmd record (or trace-cmd listen), trace-cmd restore can be
33 executed on the embedded device with the -c option to get all the
34 stored information of that embedded device. Then the file created
35 could be copied to the server to run the trace-cmd restore there
36 with the cpu files.
37 If *-o* is not specified, then the file created will be called
39 'trace-partial.dat'. This is because the file is not a full version
40 of something that trace-cmd-report(1) could use.
41 -t tracing_dir
43 Used with -c, it overrides the location to read the events from. By
44 default, tracing information is read from the debugfs/tracing
45 directory. -t will use that location instead. This can be useful
46 if the trace.dat file to create is from another machine. Just tar
47 -cvf events.tar debugfs/tracing and copy and untar that file
48 locally, and use that directory instead.
49 -k kallsyms
51 Used with -c, it overrides where to read the kallsyms file from. By
52 default, /proc/kallsyms is used. -k will override the file to read
53 the kallsyms from. This can be useful if the trace.dat file to
54 create is from another machine. Just copy the /proc/kallsyms file
55 locally, and use -k to point to that file.
56 -o output'
58 By default, trace-cmd restore will create a trace.dat file (or
59 trace-partial.dat if -c is specified). You can specify a different
60 file to write to with the -o option.
61 -i input
63 By default, trace-cmd restore will read the information of the
64 current system to create the initial data stored in the trace.dat
65 file. If the crash was on another machine, then that machine should
66 have the trace-cmd restore run with the -c option to create the
67 trace.dat partial file. Then that file can be copied to the current
68 machine where trace-cmd restore will use -i to load that file
69 instead of reading from the current system.
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72 If a crash happened on another box, you could run:
73 $ trace-cmd restore -c -o box-partial.dat
75 Then on the server that has the cpu files:
77 $ trace-cmd restore -i box-partial.dat trace.dat.cpu0 trace.dat.cpu1
79 This would create a trace.dat file for the embedded box.
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83 trace-cmd(1), trace-cmd-record(1), trace-cmd-report(1),
84 trace-cmd-start(1), trace-cmd-stop(1), trace-cmd-extract(1),
85 trace-cmd-reset(1), trace-cmd-split(1), trace-cmd-list(1),
86 trace-cmd-listen(1)
87
89 Written by Steven Rostedt, <rostedt@goodmis.org[1]>
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92 https://git.kernel.org/pub/scm/utils/trace-cmd/trace-cmd.git/
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95 Copyright (C) 2010 Red Hat, Inc. Free use of this software is granted
96 under the terms of the GNU Public License (GPL).
97
99 1. rostedt@goodmis.org
100 mailto:rostedt@goodmis.org
101libtracefs 07/22/2023 TRACE-CMD-RESTORE(1)