SYSDUMP file size

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issinoho
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SYSDUMP file size

Post by issinoho » Mon Jul 08, 2024 5:16 am

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Hardware type: QEMU Standard PC (Q35 + ICH9, 2009)
Software type: OpenVMS x86_64 V9.2-2
Physical memory: 16253216 pagelets (7936 MB)
For this system running on a 16GB drive, how big would you expect the SYSDUMP file to be?

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Physical Name   Volume Name      Type   Err   Size     Free     Used   Cap
DKA0:           X86SYS           DKX0   0  16384mb   1245mb  15139mb    92%
Here is my current dump file, which is consuming nearly half the entire disk - is this as expected?

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SYSDUMP.DMP;1         7.75GB/7.75GB
What is the recommended approach to tuning this? Manual or Autogen?


jreagan
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Re: SYSDUMP file size

Post by jreagan » Mon Jul 08, 2024 3:12 pm

I create mine with 3 15GB disks and dump to DKA100

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Device                  Device           Error   Volume          Free  Trans Mnt
 Name                   Status           Count    Label         Blocks Count Cnt
X86VMS$DKA0:            Mounted              0 X86SYS         14042096   271   1
X86VMS$DKA100:          Mounted              0 X86VMS_DUMP    19397472     1   1
X86VMS$DKA200:          Mounted              0 X86VMS_USER    29757760     1   1
I have many LPs and compilers installed and have 6.6GB free of the original 15GB. Why 2 disks and DOSD? Just habit. I should switch to SYSTEM/DUMP disk and USER disk. [I have several other drives attached that I didn't show]


dgordon
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Re: SYSDUMP file size

Post by dgordon » Mon Jul 08, 2024 3:33 pm

If one has a support contract on the system or if one actually knows how to read a dump, then it makes sense to get as much data as possible in the dump file.
Believe me, the crash code goes to great lengths to write the most important stuff first. Except in very rare occasions (usually involving issues in the dumping subsystem itself), a full dump does nothing but waste disk space and time.

AUTOGEN knows how to size dumps based on DUMPSTYLE.
Executive Vice President of InfoServer Engineering at VSI.

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issinoho
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Re: SYSDUMP file size

Post by issinoho » Thu Jul 11, 2024 5:11 am

Thanks everyone, this is a great HOWTO for future reference, especially the steps outlined by @dgordon which worked perfectly.

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