[Info-vax] Not getting a dump file when VMS crashes

[Rich Jordan]

On Apr 2, 7:36 pm, David Froble <da... at tsoft-inc.com> wrote:
> JF Mezei wrote:
> > David Froble wrote:
>
> >> $ ana/crash
> >> _Dump File: sys$system:sysdump.dmp
>
> > Don't you have to specify a dump file specification in SYSGEN  and a
> > flag to cause VMS to dump to it ?
>
> Unless I've forgotten everything I've ever known (might not be much), the contents of
> memory are written by default to SYS$SYSTEM:SYSDUMP.DMP.  I'm not trying to write the dump
> to the paging file, or DOSD (off system disk) or anything like that.  My SYSDUMP.DMP is
> the size of physical memory.

Also going from memory since its years since I tuned a VAX, but should
not SYSDUMP.DMP be larger than actual memory by some increment when
you're doing a full dump?  I don't think it was a big increment but it
was there.

Ditto on the checking the fragmentation of the dump file; contiguous
is best; we worked on (way back) a system that had run for two years
straight and had its pagefile extended in chunks and a new CBT
dumpfile made that ended up being in 20+ fragments that could not get
a valid full dump (but did succeed with a selective dump).

Perhaps worth trying DUMPSTYLE=1 (or 3) and see if a selective dump
succeeds and gives the info you need.