SET DUMP

Authorization

Privilege Class: B

Purpose

Operands

DASD

specifies that the system dump is written to one or more disks. The DASD dump space is released when the dump setting is changed. Clusters are allocated from spooling space on CP-owned DASD devices sufficient to hold a system abend dump.

rdev...

is the real device number, or a list of real device numbers of CP-owned DASD that contain spooling space to which the dump is written. A list of up to 32 real device numbers can be specified. The order in which you specify the DASD is the order in which they are searched for spooling space to be assigned as system abend dump space.

CP

is an obsolete keyword and no longer controls what memory is dumped. It is retained for compatibility.

IPL

NOIPL

indicates whether the system is to be automatically restarted after a failure. At system initialization, the value is IPL; if you do not want your system automatically restarted, you must explicitly change the setting to NOIPL.

OFF

indicates that in the event a dump is attempted, either by a CP abend, a System Restart, or SNAPDUMP command, no dump will be created.

FRMTBL DEFAULT

FRMTBL YES

FRMTBL NO

specifies whether the full CP frame table is included in a hard abend dump. If you specify DEFAULT, the frame table is included in the cases for which IBM® believes the frame table is needed to debug the problem. Otherwise, the dump includes a correlation table describing only the frames whose contents were dumped. YES forces inclusion of the frame table and NO forces the dump to have a correlation table. IBM recommends using the DEFAULT setting unless IBM support personnel instruct you to do otherwise in order to diagnose a specific problem.

PGMBKS DEFAULT

PGMBKS ALL

PGMBKS NONE

PGMBKS FAILUSER

specifies whether user PGMBKs are included in a hard abend dump. If you specify DEFAULT, PGMBKs are included in the cases for which IBM believes they are needed to debug the problem. ALL forces inclusion of all PGMBKs that aren't paged out, and NONE omits user PGMBKs. FAILUSER causes PGMBKs to be included for the guest that was running on the failing processor at the time of the abend, and for PGMBKs owned by the system. IBM recommends using the DEFAULT setting unless IBM support personnel instruct you to do otherwise in order to diagnose a specific problem.

PGMBKs owned by the system are always dumped, even if you specify PGMBKS NONE or PGMBKS FAILUSER. These PGMBKs are necessary in order to find data in address spaces owned by the system for certain VMDUMPTL commands.

Usage Notes

1. When the system is initialized, the dump device is set to DASD if there is enough spooling space to hold it. If there is not enough spooling space, a 'no dump unit' indicator is set. No dump will be generated.
2. When extending the amount of dump space during normal system execution, the system may be forced to set the 'no dump unit' indicator because there is insufficient contiguous SPOOL space.
3. The frame table and PGMBKs together constitute the vast majority of CP-owned frames, because they contain entries describing each 4K unit of real and virtual memory, respectively. The CP frame table is 1/128th the size of configured memory (8 GB per TB). PGMBKs take up 8K for each 1MB of virtual memory; though they are pageable, a PGMBK must remain resident as long as any page of that megabyte is resident. Omitting these structures from dumps when they are not likely to be needed for diagnosis dramatically reduces dump size and dumping time. With you specify the DEFAULT operand, CP determines whether or not to include the structures based on the abend code and failing module.
4. Specifying PGMBKS NONE/FAILUSER or FRMTBL NO does not affect the amount of space allocated for the dump. Dump space is allocated for a dump of maximum size because a SNAPDUMP command could occur at any time and could specify PGMBKS ALL and/or FRMTBL YES.
5. Use the OFF option only when you truly do not wish to receive a system dump. Use of this option stops the system dump capability until the command is reissued to specify an actual device.
6. When SET DUMP OFF has been specified, and the SET ABEND command was used to redefine a soft abend as HARD, an occurrence of that redefined soft abend will still cause a hard abend and a system re-IPL. But because of the SET DUMP settings, no dump will be generated. If the soft abend was redefined as SNAPDUMP, the snapdump will not be generated because the only purpose of a snapdump is to create a dump.
7. When SET DUMP OFF is specified, the hard abend dump spool file is automatically closed. This is a class D spool file that is normally opened during system initialization and is owned by the user ID specified with the DUMP operand on the SYSTEM_USERIDS configuration statement. It has a file type of "CPDUMP". Once closed, it can be reopened by issuing SET DUMP DASD or SET DUMP rdev.
8. See z/VM: CP Planning and Administration for information on Allocating Space for CP Hard Abend Dumps including recommendations from IBM.
9. Although CP limits the command length to 240 characters, not all terminal configurations allow that much input. It is possible that specifying all of the operands permitted by this command would exceed the input limits on some terminals. There are two ways to circumvent this limitation. First, it might be possible to change the line length of your terminal definition. For example, your terminal emulation software may permit you to define a terminal that has line 160 characters long, as opposed to the common line length of 80 characters. A second alternative is to create a simple REXX EXEC that contains the SET DUMP command that you wish to issue. This method has the added benefit of minimizing typographic errors because the REXX EXEC can be edited and rerun many times.

Responses

The SET DUMP command responses are the same as the QUERY DUMP command responses. For more information, see the QUERY DUMP Responses section (see QUERY DUMP).

Messages

• HCP003E Invalid option - {option|command contains extra option(s) starting with option}
• HCP006E Invalid device type - {rdev|vdev|ldev}
• HCP013E Conflicting option - option
• HCP021E A real device number was not supplied or it is invalid.
• HCP026E Operand missing or invalid
• HCP263E Too many operands were supplied for this command.
• HCP439E {User userid|*NSS|*IMG|*UCR|*NLS} spool fileid limit exceeded
• HCP847E Maximum system spool file limit exceeded
• HCP953E CP is unable to allocate system DASD dump space.
• HCP6005E Option option is not supported by z/VM.
• HCP9255I Excessive fragmentation of DASD dump space; unable to obtain additional clusters.
• HCP9259I No dump unit is set. No system abend dump will be generated. To assign a device, enter the SET DUMP command.