DUMPSTYLE is a dynamic system parameter that specifies the method of writing system dumps.
DUMPSTYLE is a 32-bit mask, with the following bits defined. Each bit can be set independently. The value of the system parameter is the sum of the values of the bits that have been set. Remaining or undefined values are reserved for VSI use only.
|0||00000001||0 = Full dump (SYSGEN default). The entire contents of physical memory are written to the dump file.
1 = Selective dump. The contents of memory are written to the dump file selectively to maximize the usefulness of the dump file while conserving disk space.
|1||00000002||0 = Minimal console output.
1 = Full console output (includes stack dump, register contents, and so on).
|2||00000004||0 = Dump to system disk.
1 = Dump off system disk (DOSD) to an alternate disk.
|3 (Alpha and Integrity)||00000008||0 = Do not compress.
1 = Compress. (VAX systems do not support dump compression.)
|4 (Alpha and Integrity)||00000010||0 = Dump shared memory.
1 = Do not dump shared memory. (VAXsystems do not support shared memory.)
|5-14||reserved for VSI use only.|
|15 (VAX only)||00008000||0 = Disable use of bits 16 - 27. (Specific to VAX 7000s.)
1 = Enable use of bits 16 - 27.
|16-27 (VAX only)||0FFF0000||Range of DOSD unit numbers. (VAX systems do not support shared memory.)|
|28-31||reserved for VSI use only.|
On Alpha and Integrity servers, you can save space on the system disk and, in the event of a crash, save time recording the system memory, by using the OpenVMS Alpha and Integrity servers dump compression feature. Unless you override the default AUTOGEN calculations (by setting DUMPSTYLE in MODPARAMS.DAT), AUTOGEN uses the following algorithm:
- On a system with less than 128 MB of memory, the system sets the DUMPSTYLE to 1 (a raw selective dump) and sizes the dump file appropriately.
- On a system with 128 MB of memory or greater, the system sets the DUMPSTYLE to 9 (a compressed selective dump), and creates the dump file at two-thirds the value of the corresponding raw dump.
The mask of 00000006 directs the system to send a full dump, with full console output, off the system disk (to the alternate disk).
For a VAX 7000, a mask of 00098006 directs the system to send a full dump with full console output to the DOSD whose unit number is 9.
On Alpha and Integrity servers, the mask of 00000009 directs the system to compress a selective dump with minimal console output.