Solved OpenVMS generating a crash dump

July 12, 2012 at 14:01:04
Specs: OpenVMS, Alpha
Should OPCCRASH.EXE generate a crash dump in either SYSDUMP or the PAGEFILE?

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#1
July 13, 2012 at 05:41:57
✔ Best Answer
The short answer is yes. A mre detailed response is as follows:

When a dump is requested (opccrash will create one), the fist target for the dump is SYSDUMP.DMP. Should that file be unavailable (or absent), the next storage spot becomes the primary pagefile. Depending upon the startup files, the dump may or may not be copied to another dumpfile from the pagefile. Please keep in mind that if not copied or otherwise released, the dump will remain in the pagefile and restrict the amount of pages available for paging.

Perhaps a better explanation of why the need for this inquiry might elicit a more detailed response.

Dan


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#2
July 13, 2012 at 10:05:06
Due to lack of contigous disk space I removed SYSDUMP.dmp to use the Pagefile for crash dumps (a recent crash was not saved; SYSDUMP too small). I am using OPCCRASH to test getting a valid dump in the Pagefile. OPCCRASH dumps to the console, but not to the Pagefile. My Pagefile is 2X the calculated SYSDUMP size.
SAVEDUMP=1, DUMPBUG=1, DUMPSTYLE=1
Thanks, Dan

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#3
July 16, 2012 at 05:23:07
More info needed here. What hardware? Memory size? Where is hte primary pagefile located? (on system disk or on another?) OpenVMS version? Reason for needing a crash dump?

Dan


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Related Solutions

#4
July 16, 2012 at 08:45:46
Alpha 4100 w/1GB of memory, VMS 6.2-1H3. I have 2 pagefiles both in the default location, SYS$SYSTEM.
---------------------------------
Physical Memory Usage (pages): Total Free In Use Modified
Main Mem (1024Mb) 131072 99212 17295 14565
-----------------
SYS$SYSROOT:[SYSEXE]
PAGEFILE.SYS;3 1052700
PAGEFILE_1.SYS;1 1052700

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#5
July 17, 2012 at 04:34:18
Set DUMPSTYLE to 9 and try again. There is not enough space in teh primary pagefile to contain the entire dump. The value of 9 will generate a compressed dumpfile that will fit in the primary pagefile. Also, please note that with SAVEDUMP set to 1, the pages consumed by the dump will remain unusable until the dump is analyzed. It is suggested that during the startup process, the dump saved to another file using the ANAL/CRASH command SAVE.

While the selective dump should have sufficient space to get something useful, I can't say for sure why you are not getting any usable crashdump without examining the entire system. Try setting the parameter as stated above and update this posting with your progress. Please note that you have not indicated why you need a crash. What problem are you attempting to resolve?

Dan


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#6
July 17, 2012 at 09:49:00
I have this in my systartup_vms:
$ANALYZE/CRASH_DUMP SYS$SYSTEM:PAGEFILE.SYS
$ copy sys$system:savedump.dmp
$ exit
I have had 2 crashes with Fatal Bug Check and/or Machine Check (ERRLOG) in the last few months, but no crash dump saved. If it happens again it would be nice to have a valid crash dump.
Thanks, Dan

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#7
July 17, 2012 at 10:05:46
Remove the $ from the copy and the exit. The $ is causing premature termination of the Anal/Crash command. Also, copy the dump to another disk and filename. Once "copied" the file is considered available and will be overwritten. Can you post the crash information listed from the operator.log file into another posting? Perhaps there will be enough there to give you an idea of the problem.

If not, then I can assist directly if we can exchange contact information.

Dan


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