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 savecrash(1M)						       savecrash(1M)




 NAME
      savecrash - save a crash dump of the operating system

 SYNOPSIS
      /sbin/savecrash [-cflprvzZ] [-D dumpdevice -O offset] [-d sysfile]

	   [-m minfree] [-s chunksize] [-t tapedevice]

	   [-w NOSWAP|SWAPEACH|SWAPEND] [dirname]

 DESCRIPTION
      savecrash saves the crash dump information of the system (assuming one
      was made when the system crashed) and writes a reboot message in the
      shutdown log file.

      dirname is the name of the existing directory in which to store the
      crash dump; the default is /var/adm/crash.

      savecrash saves the crash image and related files in the directory
      dirname/crash.n.	The trailing n in the directory name is a number
      that increases by one every time savecrash is run with the same
      dirname.	This number is kept in the file dirname/bounds, which is
      created if it does not already exist.

      Usually, savecrash creates the INDEX file in the crash directory from
      the crash dump header, copies all kernel modules that were loaded in
      memory at the time of the crash, and copies all dump device contents
      into crash image files.

      When savecrash writes out a crash dump directory, it checks the space
      available on the file system containing dirname.	savecrash will not
      use that portion of the file system space which is reserved for the
      superuser.  Additional space on the file system can be reserved for
      other uses with -m minfree, where minfree is the amount of additional
      space to reserve.	 This option is useful for ensuring enough file
      system space for normal system activities after a panic.

      If there is insufficient space in the file system for the portions of
      the crash dump that need to be saved, savecrash will save as much as
      will fit in the available space.	(Priority is given to the index
      file, then to the kernel module files, and then to the physical memory
      image.) The dump will be considered saved, and savecrash will not
      attempt to save it again, unless there was insufficient space for any
      of the physical memory image.  (See the description of option -r.)

      savecrash also writes a reboot message in the shutdown log file
      (/etc/shutdownlog), if one exists.  (If a shutdown log file does not
      exist, savecrash does not create one.) If the system crashes as a
      result of a kernel panic, savecrash also records the panic string in
      the shutdown log.




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 savecrash(1M)						       savecrash(1M)




      By default, when the primary paging device is not used as one of the
      dump devices or after the crash image on the primary paging device has
      been saved, savecrash runs in the background.  This reduces system
      boot-up time by allowing the system to be run with only the primary
      paging device.

      It is possible for dump devices to be used also as paging devices.  If
      savecrash determines that a dump device is already enabled for paging,
      and that paging activity has already taken place on that device, a
      warning message will indicate that the dump may be invalid.  If a dump
      device has not already been enabled for paging, savecrash prevents
      paging from being enabled to the device by creating the file
      /etc/savecore.LCK.  swapon does not enable the device for paging if
      the device is locked in /etc/savecore.LCK (see swapon(1M) for more
      details).	 As savecrash finishes saving the image from each dump
      device, it updates the /etc/savecore.LCK file and optionally executes
      swapon to enable paging on the device.

    Options
      -c      Mark the dump in the dump device as saved, without performing
	      any other action.	 The -c option is useful for manually
	      inhibiting dump actions called by /sbin/init.d/savecrash.

      -f      Run savecrash in the foreground only.  By default, savecrash
	      runs in the background when the primary paging device does not
	      contain an unsaved portion of the crash image.  Turning this
	      option on increases system boot-up time, but guarantees that
	      the dump has been saved when control returns to the caller.

      -l      Logs the panic information to /etc/shutdownlog as described
	      above, but does not actually save the dump.  The dump is
	      marked as saved so that future invocations of savecrash do not
	      create duplicate log entries.

      -p      Only preserves swap-endangered dump device contents into crash
	      image files.  Swap-endangered dump devices are those devices
	      that are also configured as swap devices by the system.  If
	      all dump devices are configured as swap devices, the entire
	      dump will be preserved in the crash directory.  If no swap
	      devices are used as dump devices (dedicated dump devices),
	      only the INDEX file and kernel modules will be copied into the
	      crash directory.

      -r      Resaves a dump that a previous invocation of savecrash has
	      marked as already saved.	This is useful if the first
	      invocation did ran out of space, and enough space has since
	      been freed to try again.

      -v      Enables additional progress messages and diagnostics.





 Hewlett-Packard Company	    - 2 -   HP-UX Release 11i: November 2000






 savecrash(1M)						       savecrash(1M)




      -z      savecrash will compress all physical memory image files and
	      kernel module files in the dump directory.

      -Z      savecrash will not compress any files in the dump directory.

	      If neither -z nor -Z is specified and the amount of free disk
	      space becomes less than twice the total disk space, savecrash
	      will compress the remaining files.

      -D dumpdevice
	      dumpdevice is the name of the device containing the header of
	      the raw crash image.  The console messages from the time of
	      the panic will identify the major and minor numbers of this
	      device.  This option, in combination with -O, can be used to
	      tell savecrash where to find the dump in the rare instances
	      that savecrash doesn't know where to look.

      -O offset
	      offset is the offset in kBytes, relative to the beginning of
	      the device specified with -D above, of the header of the raw
	      crash image.  The console messages from the time of the panic
	      will identify this offset.  This option, in combination with
	      -D, can be used to tell savecrash where to find the dump in
	      the rare instances that savecrash doesn't know where to look.

      -d sysfile
	      sysfile is the name of a file containing the image of the
	      system that produced the core dump (that is, the system
	      running when the crash occurred).	 If this option is not
	      specified, savecrash gets the file name from the dump itself.
	      If the file containing the image of the system that caused the
	      crash has changed, use this option to specify the new file
	      name.

      -m minfree
	      minfree is the amount of free space (in kBytes) that must
	      remain free for ordinary user files after savecrash completes,
	      in addition to space reserved for the superuser.	If
	      necessary, only part of the dump will be saved to achieve this
	      requirement.  minfree may be specified in bytes (b), kilobytes
	      (k), megabytes (m), or gigabytes (g).  The default minfree
	      value is zero, and the default unit is kilobytes.

      -s chunksize
	      chunksize is the size (default kBytes) of a single physical
	      memory image file before compression.  The kByte value must be
	      a multiple of page size (divisible by 4) and between 64 and
	      1048576.	chunksize may be specified in units of bytes (b),
	      kilobytes (k), megabytes (m), or gigabytes (g).  Larger
	      numbers increase compression efficiency at the expense of both
	      savecrash time and debugging time.  If -s is not specified, a



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 savecrash(1M)						       savecrash(1M)




	      default is chosen based on the physical memory size and the
	      amount of available file system space.

      -t tapedevice
	      tapedevice is the tape device where the crash dump will be
	      written.	Crash dumps that are written to tape are written
	      using a tar format.  The crash dump tape can be read using
	      tar(1).

	      When the -t option is specified, the -p option is not allowed
	      and the whole dump is always preserved.  In addition, -c and
	      -l, are not allowed and -m is ignored.  Also, when -t is
	      specified, savecrash will not perform any compression.

	      When dirname is specified with the -t option, dirname is the
	      name of the existing directory where the INDEX file is
	      created; the default directory is /tmp.  The INDEX file is the
	      first file that is written out to the dump tape.	This file is
	      written a second time once all the dump files have been
	      written.	The first copy of the file only contains crash dump
	      header information and its filename on tape is tmpindex.	It
	      does not contain information for the module and image files.

	      When writing to tape, the tape device must be online otherwise
	      the command will fail with an error.  Additionally, when
	      savecrash reaches end-of-tape, it will prompt the user for the
	      next tape.  Any tape errors encountered will result in a
	      generic tape error.

      -w opt  Defines the interaction between savecrash and swapon.  opt can
	      be one of the following values:

	      NOSWAP	  Do not run swapon from savecrash.

	      SWAPEACH	  (default) Call swapon each time savecrash finishes
			  saving the image from each dump device.  This
			  option provides the most efficient use of paging
			  space.

	      SWAPEND	  Only call swapon when savecrash finishes saving
			  the image file from all dump devices.	 If this
			  option is used, no additional paging space other
			  than the primary paging space is available until
			  the complete crash dump image is saved.  This
			  option provides a second chance to retrieve the
			  crash image if savecrash fails on first attempt.

	      For compatibility with earlier savecore syntax, the values of
	      0, 1 and 2 can be used in place of NOSWAP, SWAPEACH, and
	      SWAPEND, respectively.  This usage is obsolescent.




 Hewlett-Packard Company	    - 4 -   HP-UX Release 11i: November 2000






 savecrash(1M)						       savecrash(1M)




 RETURN VALUE
      Upon exit, savecrash returns the following values:

	   0	A crash dump was found and saved, or savecrash has preserved
		dump information from the primary swap device and is
		continuing to run in the background to complete its tasks.
	   1	A crash dump could not be saved due to an error.
	   2	No crash dump was found to save.
	   3	A partial crash dump was saved, but there was insufficient
		space to preserve the complete dump.
	   4	The savecrash process continued in the background, see the
		INDEX file for actual results.

 WARNINGS
      savecrash relies on the expectation that device numbers have the same
      meaning (point to the same devices) at the time the system dumps and
      at the time the dump is saved.  If, after a crash, the system was
      booted from a different boot device in order to run savecrash, it is
      possible that this expectation will not be met.  If so, savecrash may
      save an incomplete or incorrect dump or may fail to save a dump at
      all.  Such cases cannot be reliably detected, so there may be no
      warning or error message.

      If savecrash encounters an error while running in the background (such
      as running out of space), it will not be easily detectable by the
      caller.  If the caller must ensure that the savecrash operation was
      successful, for example before writing to a dump device, the caller
      should specify -f to force savecrash to run in the foreground, and
      should then examine the exit status of the savecrash process when it
      finishes.

 AUTHOR
      savecrash was developed by HP and the University of California,
      Berkeley.

 FILES
      /etc/shutdownlog			      shutdown log
      /etc/rc.config.d/savecrash	      savecrash startup
					      configuration file
      /sbin/init.d/savecrash		      savecrash startup file
      dirname/bounds			      crash dump number
      /stand/vmunix			      default kernel image saved by
					      savecrash

 SEE ALSO
      adb(1), crashutil(1M), swapon(1M), tar(1).








 Hewlett-Packard Company	    - 5 -   HP-UX Release 11i: November 2000