1MAKEDUMPFILE(8)       Linux System Administrator's Manual      MAKEDUMPFILE(8)
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NAME

6       makedumpfile - make a small dumpfile of kdump
7

SYNOPSIS

9       makedumpfile    [OPTION] [-x VMLINUX|-i VMCOREINFO] VMCORE DUMPFILE
10       makedumpfile -F [OPTION] [-x VMLINUX|-i VMCOREINFO] VMCORE
11       makedumpfile   [OPTION] -x VMLINUX [--config FILTERCONFIGFILE] [--eppic
12       EPPICMACRO] VMCORE DUMPFILE
13       makedumpfile -R DUMPFILE
14       makedumpfile --split [OPTION] [-x VMLINUX|-i VMCOREINFO]  VMCORE  DUMP‐
15       FILE1 DUMPFILE2 [DUMPFILE3 ..]
16       makedumpfile  [OPTION] [-x VMLINUX|-i VMCOREINFO] --num-threads THREAD‐
17       NUM VMCORE DUMPFILE
18       makedumpfile --reassemble DUMPFILE1 DUMPFILE2 [DUMPFILE3 ..] DUMPFILE
19       makedumpfile -g VMCOREINFO -x VMLINUX
20       makedumpfile    [OPTION] [--xen-syms XEN-SYMS|--xen-vmcoreinfo  VMCORE‐
21       INFO] VMCORE DUMPFILE
22       makedumpfile  --dump-dmesg [--partial-dmesg] [-x VMLINUX|-i VMCOREINFO]
23       VMCORE LOGFILE
24       makedumpfile    [OPTION] -x VMLINUX --diskset=VMCORE1 --diskset=VMCORE2
25       [--diskset=VMCORE3 ..] DUMPFILE
26       makedumpfile -h
27       makedumpfile -v
28

DESCRIPTION

30       With kdump, the memory image of the first kernel (called "panicked ker‐
31       nel") can be taken as /proc/vmcore  while  the  second  kernel  (called
32       "kdump  kernel"  or  "capture kernel") is running. This document repre‐
33       sents /proc/vmcore as VMCORE. makedumpfile makes a  small  DUMPFILE  by
34       compressing  dump  data or by excluding unnecessary pages for analysis,
35       or both. makedumpfile needs the first kernel's  debug  information,  so
36       that  it  can  distinguish unnecessary pages by analyzing how the first
37       kernel uses the memory.  The information can be taken from  VMLINUX  or
38       VMCOREINFO.
39
40       makedumpfile  can  exclude  the  following types of pages while copying
41       VMCORE to DUMPFILE, and a user can choose which type of pages  will  be
42       excluded.
43       - Pages filled with zero
44       - Cache pages without private flag (non-private cache)
45       - Cache pages with private flag (private cache)
46       - User process data pages
47       - Free pages
48
49       makedumpfile  provides  two  DUMPFILE  formats  (the ELF format and the
50       kdump-compressed format). By default, makedumpfile makes a DUMPFILE  in
51       the  kdump-compressed  format.  The kdump-compressed format is readable
52       only with the crash utility, and it can be smaller than the ELF  format
53       because of the compression support. The ELF format is readable with GDB
54       and the crash utility.  If a user wants to use GDB, DUMPFILE format has
55       to be explicitly specified to be the ELF format.
56
57       Apart  from  the  exclusion of unnecessary pages mentioned above, make‐
58       dumpfile allows user to filter out targeted  kernel  data.  The  filter
59       config  file  can be used to specify kernel/module symbols and its mem‐
60       bers that need to be filtered out through  the  erase  command  syntax.
61       makedumpfile  reads  the  filter  config  and builds the list of memory
62       addresses and its sizes after processing filter  commands.  The  memory
63       locations  that require to be filtered out are then poisoned with char‐
64       acter 'X' (58 in Hex). Refer to makedumpfile.conf(5) for file format.
65
66       Eppic macros can also be used to specify kernel symbols and its members
67       that need to be filtered. Eppic provides C semantics including language
68       constructs such as conditional statements, logical and arithmetic oper‐
69       ators,  functions,  nested  loops  to  traverse  and erase kernel data.
70       --eppic requires eppic_makedumpfile.so and eppic  library.  eppic_make‐
71       dumpfile.so   can   be   built   from  makedumpfile  source.  Refer  to
72       http://code.google.com/p/eppic/ to build eppic library  libeppic.a  and
73       for more information on writing eppic macros.
74
75       To  analyze  the first kernel's memory usage, makedumpfile can refer to
76       VMCOREINFO instead of VMLINUX. VMCOREINFO contains the  first  kernel's
77       information  (structure  size,  field  offset, etc.), and VMCOREINFO is
78       small enough to be included into the second kernel's initrd.
79       If the second kernel is running on its initrd without mounting  a  root
80       file  system,  makedumpfile  cannot refer to VMLINUX because the second
81       kernel's initrd cannot include a large file like VMLINUX. To solve  the
82       problem,  makedumpfile  makes  VMCOREINFO  beforehand, and it refers to
83       VMCOREINFO instead of VMLINUX while the second kernel is running.
84       VMCORE has contained VMCOREINFO since linux-2.6.24, and a user does not
85       need to specify neither -x nor -i option.
86
87       If the second kernel is running on its initrd without mounting any file
88       system, a user needs to transport the dump data to a  remote  host.  To
89       transport  the  dump data by SSH, makedumpfile outputs the dump data in
90       the intermediate format (the flattened format) to the standard  output.
91       By piping the output data to SSH, a user can transport the dump data to
92       a remote host. Note that analysis tools (crash utility  before  version
93       5.1.2 or GDB) cannot read the flattened format directly, so on a remote
94       host the received data in the flattened format needs to  be  rearranged
95       to a readable DUMPFILE format by makedumpfile (or makedumpfile-R.pl).
96
97       makedumpfile can read a DUMPFILE in the kdump-compressed format instead
98       of VMCORE and re-filter it. This feature is useful  in  situation  that
99       users need to reduce the file size of DUMPFILE for sending it somewhere
100       by ftp/scp/etc. (If all of the page types, which are specified by a new
101       dump_level, are excluded from an original DUMPFILE already, a new DUMP‐
102       FILE is the same as an original DUMPFILE.)
103       For example, makedumpfile can create a DUMPFILE of dump_level  31  from
104       the one of dump_level 3 like the following:
105       Example:
106       # makedumpfile -c -d 3 /proc/vmcore dumpfile.1
107       # makedumpfile -c -d 31 dumpfile.1 dumpfile.2
108
109       makedumpfile  can read VMCORE(s) in three kinds of sadump formats: sin‐
110       gle partition format, diskset format and media backup format,  and  can
111       convert  each  of  them into kdump-compressed format with filtering and
112       compression processing. Note that for VMCORE(s) created by sadump,  you
113       always  need  to  pass  VMLINUX  with -x option. Also, to pass multiple
114       VMCOREs created on diskset configuration, you  need  to  use  --diskset
115       option.
116
117

OPTIONS

119       -c,-l,-p
120              Compress  dump  data  by each page using zlib for -c option, lzo
121              for -l option  or  snappy  for  -p  option.   (-l  option  needs
122              USELZO=on and -p option needs USESNAPPY=on when building)
123              A  user  cannot  specify this option with -E option, because the
124              ELF format does not support compressed data.
125              Example:
126              # makedumpfile -c -d 31 -x vmlinux /proc/vmcore dumpfile
127
128
129       -d dump_level
130              Specify the type of unnecessary page for analysis.
131              Pages of the specified type are not copied to DUMPFILE. The page
132              type marked in the following table is excluded. A user can spec‐
133              ify multiple page types by setting the sum of each page type for
134              dump_level.  The  maximum  of  dump_level  is  31.  Note  that a
135              dump_level for Xen dump filtering is 0 or 1 on a  machine  other
136              than  x86_64.  On  a x86_64 machine, even 2 or bigger dump level
137              will be effective if you  specify  domain-0's  vmlinux  with  -x
138              option.  Then the pages are excluded only from domain-0.
139              If specifying multiple dump_levels with the delimiter ',', make‐
140              dumpfile retries to create a DUMPFILE by other  dump_level  when
141              "No  space  on device" error happens. For example, if dump_level
142              is "11,31" and makedumpfile fails by dump_level 11, makedumpfile
143              retries it by dump_level 31.
144              Example:
145              # makedumpfile -d 11 -x vmlinux /proc/vmcore dumpfile
146              # makedumpfile -d 11,31 -x vmlinux /proc/vmcore dumpfile
147              Base level:
148              dump_level  consists of five bits, so there are five base levels
149              to specify the type of unnecessary page.
150                    1 : Exclude the pages filled with zero.
151                    2 : Exclude the non-private cache pages.
152                    4 : Exclude all cache pages.
153                    8 : Exclude the user process data pages.
154                   16 : Exclude the free pages.
155
156              Here is the all combinations of the bits.
157
158                     |      |non-   |       |      |
159                dump | zero |private|private| user | free
160               level | page |cache  |cache  | data | page
161              -------+------+-------+-------+------+------
162                   0 |      |       |       |      |
163                   1 |  X   |       |       |      |
164                   2 |      |   X   |       |      |
165                   3 |  X   |   X   |       |      |
166                   4 |      |   X   |   X   |      |
167                   5 |  X   |   X   |   X   |      |
168                   6 |      |   X   |   X   |      |
169                   7 |  X   |   X   |   X   |      |
170                   8 |      |       |       |  X   |
171                   9 |  X   |       |       |  X   |
172                  10 |      |   X   |       |  X   |
173                  11 |  X   |   X   |       |  X   |
174                  12 |      |   X   |   X   |  X   |
175                  13 |  X   |   X   |   X   |  X   |
176                  14 |      |   X   |   X   |  X   |
177                  15 |  X   |   X   |   X   |  X   |
178                  16 |      |       |       |      |  X
179                  17 |  X   |       |       |      |  X
180                  18 |      |   X   |       |      |  X
181                  19 |  X   |   X   |       |      |  X
182                  20 |      |   X   |   X   |      |  X
183                  21 |  X   |   X   |   X   |      |  X
184                  22 |      |   X   |   X   |      |  X
185                  23 |  X   |   X   |   X   |      |  X
186                  24 |      |       |       |  X   |  X
187                  25 |  X   |       |       |  X   |  X
188                  26 |      |   X   |       |  X   |  X
189                  27 |  X   |   X   |       |  X   |  X
190                  28 |      |   X   |   X   |  X   |  X
191                  29 |  X   |   X   |   X   |  X   |  X
192                  30 |      |   X   |   X   |  X   |  X
193                  31 |  X   |   X   |   X   |  X   |  X
194
195
196
197       -E     Create DUMPFILE in the ELF format.
198              This option cannot be specified with the -c, -l or  -p  options,
199              because the ELF format does not support compressed data.
200              Example:
201              # makedumpfile -E -d 31 -x vmlinux /proc/vmcore dumpfile
202
203
204       -f     Force  existing DUMPFILE to be overwritten and mem-usage to work
205              with older kernel as well.
206              Example:
207              # makedumpfile -f -d 31 -x vmlinux /proc/vmcore dumpfile
208              This command overwrites DUMPFILE even if it already exists.
209              # makedumpfile -f --mem-usage /proc/kcore
210              Kernel version lesser than v4.11 will not work with  --mem-usage
211              functionality  until  it  has  been patched with upstream commit
212              464920104bf7.  Therefore if you have patched your  older  kernel
213              then use -f.
214
215
216       -x VMLINUX
217              Specify  the  first  kernel's  VMLINUX with debug information to
218              analyze the first kernel's memory usage.
219              This option is necessary if VMCORE does not contain  VMCOREINFO,
220              [-i VMCOREINFO] is not specified, and dump_level is 2 or more.
221              The  page  size of the first kernel and the second kernel should
222              match.
223              Example:
224              # makedumpfile -d 31 -x vmlinux /proc/vmcore dumpfile
225
226
227       -i VMCOREINFO
228              Specify VMCOREINFO instead of VMLINUX for  analyzing  the  first
229              kernel's memory usage.
230              VMCOREINFO  should  be  made  beforehand by makedumpfile with -g
231              option, and it contains the first kernel's information.
232              This option is necessary if VMCORE does not contain  VMCOREINFO,
233              [-x VMLINUX] is not specified, and dump_level is 2 or more.
234              Example:
235              # makedumpfile -d 31 -i vmcoreinfo /proc/vmcore dumpfile
236
237
238       -g VMCOREINFO
239              Generate  VMCOREINFO  from the first kernel's VMLINUX with debug
240              information.
241              VMCOREINFO must be generated on the system that is  running  the
242              first kernel. With -i option, a user can specify VMCOREINFO gen‐
243              erated on the other system that is running the same  first  ker‐
244              nel. [-x VMLINUX] must be specified.
245              Example:
246              # makedumpfile -g vmcoreinfo -x vmlinux
247
248
249       --config FILTERCONFIGFILE
250              Used  in conjunction with -x VMLINUX option, to specify the fil‐
251              ter config file FILTERCONFIGFILE that contains erase commands to
252              filter  out desired kernel data from vmcore while creating DUMP‐
253              FILE. For  filter  command  syntax  please  refer  to  makedump‐
254              file.conf(5).
255
256
257       --eppic EPPICMACRO
258              Used in conjunction with -x VMLINUX option, to specify the eppic
259              macro file that contains filter rules or directory that contains
260              eppic  macro files to filter out desired kernel data from vmcore
261              while creating DUMPFILE.  When directory is specified,  all  the
262              eppic macros in the directory are processed.
263
264
265       -F     Output  the  dump  data  in the flattened format to the standard
266              output for transporting the dump data by SSH.
267              Analysis tools (crash utility before version 5.1.2 or GDB)  can‐
268              not  read  the flattened format directly. For analysis, the dump
269              data in the flattened format should be rearranged  to  a  normal
270              DUMPFILE  (readable  with analysis tools) by -R option. By which
271              option is specified with -F option, the format of the rearranged
272              DUMPFILE  is fixed.  In other words, it is impossible to specify
273              the DUMPFILE format when the dump data  is  rearranged  with  -R
274              option.  If  specifying  -E option with -F option, the format of
275              the rearranged DUMPFILE is the ELF format. Otherwise, it is  the
276              kdump-compressed format. All the messages are output to standard
277              error output by -F option because standard output  is  used  for
278              the dump data.
279              Example:
280              # makedumpfile -F -c -d 31 -x vmlinux /proc/vmcore \
281              | ssh user@host "cat > dumpfile.tmp"
282              # makedumpfile -F -c -d 31 -x vmlinux /proc/vmcore \
283              | ssh user@host "makedumpfile -R dumpfile"
284              # makedumpfile -F -E -d 31 -i vmcoreinfo  /proc/vmcore \
285              | ssh user@host "makedumpfile -R dumpfile"
286              # makedumpfile -F -E --xen-vmcoreinfo VMCOREINFO /proc/vmcore \
287              | ssh user@host "makedumpfile -R dumpfile"
288
289
290       -R     Rearrange  the  dump data in the flattened format from the stan‐
291              dard input to a normal DUMPFILE (readable with analysis tools).
292              Example:
293              # makedumpfile -R dumpfile < dumpfile.tmp
294              # makedumpfile -F -d 31 -x vmlinux /proc/vmcore \
295              | ssh user@host "makedumpfile -R dumpfile"
296
297              Instead of using -R option, a  perl  script  "makedumpfile-R.pl"
298              rearranges  the  dump  data  in the flattened format to a normal
299              DUMPFILE, too. The perl script does not depend on  architecture,
300              and  most systems have perl command.  Even if a remote host does
301              not have makedumpfile, it is possible to rearrange the dump data
302              in  the flattened format to a readable DUMPFILE on a remote host
303              by running this script.
304              Example:
305              # makedumpfile -F -d 31 -x vmlinux /proc/vmcore \
306              | ssh user@host "makedumpfile-R.pl dumpfile"
307
308
309       --split
310              Split the dump data to multiple DUMPFILEs in parallel. If speci‐
311              fying DUMPFILEs on different storage devices, a device can share
312              I/O load with other devices and it reduces time for  saving  the
313              dump  data.  The  file size of each DUMPFILE is smaller than the
314              system memory size which is divided by the number of  DUMPFILEs.
315              This feature supports only the kdump-compressed format.
316              Example:
317              #  makedumpfile  --split -d 31 -x vmlinux /proc/vmcore dumpfile1
318              dumpfile2
319
320
321       --num-threads THREADNUM
322              Using multiple threads to read and compress data of each page in
323              parallel.   And  it will reduces time for saving DUMPFILE.  Note
324              that if the usable cpu number is less than the thread number, it
325              may  lead  to  great performance degradation.  This feature only
326              supports creating DUMPFILE in kdump-comressed format from VMCORE
327              in kdump-compressed format or elf format.
328              Example:
329              # makedumpfile -d 31 --num-threads 4 /proc/vmcore dumpfile
330
331
332       --reassemble
333              Reassemble  multiple  DUMPFILEs,  which  are  created by --split
334              option, into one DUMPFILE. dumpfile1 and dumpfile2 are  reassem‐
335              bled into dumpfile on the following example.
336              Example:
337              # makedumpfile --reassemble dumpfile1 dumpfile2 dumpfile
338
339
340       -b <order>
341              Cache 2^order pages in ram when generating DUMPFILE before writ‐
342              ing to output.  The default value is 4.
343
344
345       --cyclic-buffer buffer_size
346              Specify the buffer size in kilo bytes for bitmap data.   Filter‐
347              ing processing will be divided into multi cycles to fix the mem‐
348              ory consumption, the number of cycles is represented as:
349
350                  num_of_cycles  =  system_memory  /  (buffer_size  *  1024  *
351              bit_per_bytes * page_size )
352
353              The  lesser  number  of  cycles,  the  faster  working  speed is
354              expected.  By default, buffer_size will be calculated  automati‐
355              cally  depending  on system memory size, so ordinary users don't
356              need to specify this option.
357
358              Example:
359              #  makedumpfile  --cyclic-buffer   1024   -d   31   -x   vmlinux
360              /proc/vmcore dumpfile
361
362
363       --splitblock-size splitblock_size
364              Specify  the  splitblock  size  in  kilo bytes for analysis with
365              --split.  If --splitblock N is  specified,  difference  of  each
366              splitted dumpfile size is at most N kilo bytes.
367              Example:
368              #  makedumpfile  --splitblock-size 1024 -d 31 -x vmlinux --split
369              /proc/vmcore dumpfile1 dumpfile2
370
371
372
373       --work-dir
374              Specify the working directory for the temporary bitmap file.  If
375              this option isn't specified, the bitmap will be saved on memory.
376              Filtering processing has to do 2 pass scanning to fix the memory
377              consumption, but it can be avoided by using working directory on
378              file system.  So if you specify this option, the filtering speed
379              may be bit faster.
380
381              Example:
382              #  makedumpfile  --work-dir  /tmp  -d 31 -x vmlinux /proc/vmcore
383              dumpfile
384
385
386       --non-mmap
387              Never use mmap(2) to read VMCORE even if  it  supports  mmap(2).
388              Generally,  reading  VMCORE  with mmap(2) is faster than without
389              it, so ordinary users don't need to specify this  option.   This
390              option is mainly for debugging.
391              Example:
392              # makedumpfile --non-mmap -d 31 -x vmlinux /proc/vmcore dumpfile
393
394
395       --xen-syms XEN-SYMS
396              Specify the XEN-SYMS with debug information to analyze the xen's
397              memory  usage.   This  option  extracts  the  part  of  xen  and
398              domain-0.
399              Example:
400              # makedumpfile -E --xen-syms xen-syms /proc/vmcore dumpfile
401
402
403       --xen-vmcoreinfo VMCOREINFO
404              Specify  VMCOREINFO  instead of XEN-SYMS for analyzing the xen's
405              memory usage.
406              VMCOREINFO should be made beforehand  by  makedumpfile  with  -g
407              option, and it contains the xen's information.
408              Example:
409              # makedumpfile -E --xen-vmcoreinfo VMCOREINFO /proc/vmcore dump‐
410              file
411
412
413       -X     Exclude all the user domain pages from Xen kdump's  VMCORE,  and
414              extracts the part of xen and domain-0. If VMCORE contains VMCOR‐
415              EINFO for Xen, it is not necessary  to  specify  --xen-syms  and
416              --xen-vmcoreinfo.
417              Example:
418              # makedumpfile -E -X /proc/vmcore dumpfile
419
420
421       --xen_phys_start xen_phys_start_address
422              This    option    is    only    for    x86_64.     Specify   the
423              xen_phys_start_address, if the xen code/data is relocatable  and
424              VMCORE does not contain xen_phys_start_address in the CRASHINFO.
425              xen_phys_start_address can be taken from the line of "Hypervisor
426              code  and  data" in /proc/iomem. For example, specify 0xcee00000
427              as xen_phys_start_address if /proc/iomem is the following:
428                -------------------------------------------------------
429                # cat /proc/iomem
430                ...
431                  cee00000-cfd99999 : Hypervisor code and data
432                ...
433                -------------------------------------------------------
434
435              Example:
436              # makedumpfile -E -X  --xen_phys_start  0xcee00000  /proc/vmcore
437              dumpfile
438
439
440       --message-level message_level
441              Specify the message types.
442              Users  can  restrict outputs printed by specifying message_level
443              with this option. The message type marked with an X in the  fol‐
444              lowing  table  is  printed. For example, according to the table,
445              specifying 7 as message_level means progress  indicator,  common
446              message,  and  error  message are printed, and this is a default
447              value. Note that the maximum value of message_level is 31.
448
449               message | progress | common  | error   | debug   | report
450               level   | indicator| message | message | message | message
451              ---------+----------+---------+---------+---------+---------
452                     0 |          |         |         |         |
453                     1 |    X     |         |         |         |
454                     2 |          |    X    |         |         |
455                     3 |    X     |    X    |         |         |
456                     4 |          |         |    X    |         |
457                     5 |    X     |         |    X    |         |
458                     6 |          |    X    |    X    |         |
459                   * 7 |    X     |    X    |    X    |         |
460                     8 |          |         |         |    X    |
461                     9 |    X     |         |         |    X    |
462                    10 |          |    X    |         |    X    |
463                    11 |    X     |    X    |         |    X    |
464                    12 |          |         |    X    |    X    |
465                    13 |    X     |         |    X    |    X    |
466                    14 |          |    X    |    X    |    X    |
467                    15 |    X     |    X    |    X    |    X    |
468                    16 |          |         |         |         |    X
469                    17 |    X     |         |         |         |    X
470                    18 |          |    X    |         |         |    X
471                    19 |    X     |    X    |         |         |    X
472                    20 |          |         |    X    |         |    X
473                    21 |    X     |         |    X    |         |    X
474                    22 |          |    X    |    X    |         |    X
475                    23 |    X     |    X    |    X    |         |    X
476                    24 |          |         |         |    X    |    X
477                    25 |    X     |         |         |    X    |    X
478                    26 |          |    X    |         |    X    |    X
479                    27 |    X     |    X    |         |    X    |    X
480                    28 |          |         |    X    |    X    |    X
481                    29 |    X     |         |    X    |    X    |    X
482                    30 |          |    X    |    X    |    X    |    X
483                    31 |    X     |    X    |    X    |    X    |    X
484
485
486       --vtop virtual_address
487              This option is useful, when user debugs the translation  problem
488              of  virtual  address. If specifing virtual_address, its physical
489              address is printed. It makes debugging  easy  by  comparing  the
490              output  of  this option with the one of "vtop" subcommand of the
491              crash utility.  "--vtop" option only prints the translation out‐
492              put, and it does not affect the dumpfile creation.
493
494
495       --dump-dmesg
496              This  option  overrides  the  normal  behavior  of makedumpfile.
497              Instead of  compressing  and  filtering  a  VMCORE  to  make  it
498              smaller,  it  simply  extracts  the  dmesg log from a VMCORE and
499              writes it to the specified LOGFILE. If a VMCORE does not contain
500              VMCOREINFO for dmesg, it is necessary to specfiy [-x VMLINUX] or
501              [-i VMCOREINFO].
502
503              Example:
504              # makedumpfile --dump-dmesg /proc/vmcore dmesgfile
505              # makedumpfile --dump-dmesg -x vmlinux /proc/vmcore dmesgfile
506
507
508
509       --partial-dmesg
510              This option will make --dump-dmesg extract only dmesg logs since
511              that  buffer  was  last  cleared  on the crashed kernel, through
512              "dmesg --clear" for example.
513
514
515
516       --mem-usage
517              This option is currently supported on x86_64, arm64,  ppc64  and
518              s390x.   This option is used to show the page numbers of current
519              system in different use. It should be executed in 1st kernel. By
520              the  help of this, user can know how many pages is dumpable when
521              different dump_level is specified. It analyzes the 'System  Ram'
522              and  'kernel  text' program segment of /proc/kcore excluding the
523              crashkernel range, then calculates the page number of  different
524              kind  per vmcoreinfo. So currently /proc/kcore need be specified
525              explicitly.
526
527              Example:
528              # makedumpfile --mem-usage /proc/kcore
529
530
531
532       --diskset=VMCORE
533              Specify multiple VMCOREs created on sadump diskset configuration
534              the  same number of times as the number of VMCOREs in increasing
535              order from left to right.  VMCOREs are assembled into  a  single
536              DUMPFILE.
537
538              Example:
539              #  makedumpfile  -x  vmlinux --diskset=vmcore1 --diskset=vmcore2
540              dumpfile
541
542
543       -D     Print debugging message.
544
545
546       -h (--help)
547              Show help message and LZO/snappy  support  status  (enabled/dis‐
548              abled).
549
550
551       -v     Show the version of makedumpfile.
552
553
554       --check-params
555              Only check whether the command-line parameters are valid or not,
556              and exit.  Preferable to be given as the first parameter.
557
558

ENVIRONMENT VARIABLES

560       TMPDIR  This environment variable is used in 1st kernel environment for
561               a  temporary memory bitmap file.  If your machine has a lots of
562               memory and you use small tmpfs on /tmp, makedumpfile  can  fail
563               for  a  little  memory  because makedumpfile makes a very large
564               temporary memory bitmap file in this case. To avoid this  fail‐
565               ure, you should specify --work-dir option to use file system on
566               storage for the bitmap file.
567
568

DIAGNOSTICS

570       makedumpfile exits with the following value.
571
572       0 : makedumpfile succeeded.
573
574       1 : makedumpfile failed without the following reasons.
575
576       2 : makedumpfile failed due to the different version  between   VMLINUX
577       and VMCORE.
578
579

AUTHORS

581       Written by Masaki Tachibana, and Ken'ichi Ohmichi.
582
583

SEE ALSO

585       crash(8), gdb(1), kexec(8), makedumpfile.conf(5)
586
587
588
589
590makedumpfile v1.6.8               16 Nov 2020                  MAKEDUMPFILE(8)
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