dump_compress_on(5) [hpux man page]

dump_compress_on(5)						File Formats Manual					       dump_compress_on(5)

NAME

       dump_compress_on - selects whether the system dumps memory pages compressed or uncompressed when a kernel panic occurs

VALUES

   Failsafe
   Default
       (Allow the kernel to decide whether to dump compressed or not based on the system state at the time of the crash.)

   Allowed value
       Integer values and

       The setting for is used as follows:

	      Dump uncompressed.

	      Dump with compression for speed if possible.

   Recommended values
       (Allow the kernel to choose dump mode.)

       The value the kernel usually chooses is 1.

DESCRIPTION

       On large systems, the time required to dump system memory when a kernel panic occurs can be excessive or even prohibitive, depending on how
       much physical memory is installed in the system.  Compressed dump capability results in smaller and faster dumps that will also take lesser
       time to save over into the filesystem.

       The (see crashconf(1M)) command and its associated configuration file control the dump compression mode in the memory dumps associated with
       a system crash.	On rare occasions, the system may crash before is run during the boot process.	On those occasions, the configuration  set
       using the tunable will be used.

       The  default value for this parameter is The system determines whether or not to dump compressed based on the type of crash that occurs, in
       this case.

       Note that certain types of system crash require an uncompressed crash dump.  Also, the system operator may request  an  uncompressed  crash
       dump at the time the dump is taken.  In either of these cases, an uncompressed dump will be performed regardless of the mode selected in

   Who Is Expected to Change This Tunable?
       Only HP Field engineers should change the value of this tunable.

   Restrictions on Changing
       Changes to this tunable take effect immediately.

   When Should the Tunable Be Turned On?
       This tunable should be turned on to dump compressed when there is a system crash.

   What Are the Side Effects of Turning the Tunable Off?
       In  this case, an uncompressed dump is taken always.  On large memory machines, an uncompressed dump take typically three times longer than
       a compressed dump.

   When Should the Tunable Be Turned Off?
       The tunable should be turned off if there is a problem with compressed dumps.

   What Are the Side Effects of Turning the Tunable On?
       The system decides the dump mode based on the type of crash.

   What Other Tunables Should Be Changed at the Same Time?
       None.

WARNINGS

       All HP-UX kernel tunable parameters are release specific.  This parameter may be removed or have its meaning changed in future releases	of
       HP-UX.

       Installation  of  optional  kernel  software, from HP or other vendors, may cause changes to tunable parameter values.  After installation,
       some tunable parameters may no longer be at the default or recommended values.  For information about the effects of installation  on  tun-
       able  values,  consult  the documentation for the kernel software being installed.  For information about optional kernel software that was
       factory installed on your system, see at

AUTHOR

       was developed by Hewlett-Packard Company.

SEE ALSO

       crashconf(1M), alwaysdump(5), dontdump(5).

							     Tunable Kernel Parameters					       dump_compress_on(5)

Check Out this Related Man Page

core_addshmem_read(5)						File Formats Manual					     core_addshmem_read(5)

NAME

       core_addshmem_read - determines the inclusion of readable shared memory in a process core dump

VALUES

   Failsafe
   Default
   Allowed values
       or

DESCRIPTION

       The  tunable  was added in response to a problem where a customer was limited in debugging a user-level process crash because shared memory
       segments were not written as part of the core file.

       Upon core dump, the sections of user memory labeled as shared read-only are written (along with the normal data sections) if  this  tunable
       is set to and left out if it is set to

   Who is Expected to Change This Tunable?
       Anyone.

   Restrictions on Changing
       Changes to this tunable take effect immediately.

   When Should the Value of This Tunable Be Raised?
       When  you  wish	to  include read-only shared memory segments in user core files due to debugging needs by developers or maintainers on the
       system.

   What Are the Side Effects of Raising the Value?
       User process core files would increase in most cases (most applications use at least some shared memory).  This could be a problem on  sys-
       tems where disk space is at a premium.

   When Should the Value of This Tunable Be Lowered?
       When there is no need for debugging core files where shared memory corruption or data values are in question.

   What Are the Side Effects of Lowering the Value?
       Core files will tend to be smaller.

   What Other Tunable Values Should Be Changed at the Same Time?
       Certainly think about which does the same thing for read/write shared memory segments.

WARNINGS

       All  HP-UX kernel tunable parameters are release specific.  This parameter may be removed or have its meaning changed in future releases of
       HP-UX.

       Installation of optional kernel software, from HP or other vendors, may cause changes to tunable  parameter  values.   After  installation,
       some  tunable  parameters may no longer be at the default or recommended values.  For information about the effects of installation on tun-
       able values, consult the documentation for the kernel software being installed.	For information about optional kernel  software  that  was
       factory installed on your system, see at

AUTHOR

       was developed by HP.

							     Tunable Kernel Parameters					     core_addshmem_read(5)

Linux and UNIX Man Pages

dump_compress_on(5) [hpux man page]

Check Out this Related Man Page