Resizing the sysdump.dmp file

[John A. Beard]

Hi,

I would appreciate some advice on the following sysdump issue.

Platform - ES47
Operating System - OpenVMS 7.3-2

Curent sysdump.dmp size 681k blocks on sys$sysdevice

Required new size 2.25 million blocks bases on autogen report -

Dump file calculations:

A 2258830 block dump file should be created.

Free space on sys$sysdevice 4.5 million blocks

sysgen > current dumpstyle = 9

modparams.dat

!DUMPFILE=0
!DUMPSTYLE=13

Q. Can we simply run sys$update:swapfiles and create a new version of the dump file with the new block size vale, reboot and purge out the original version. The disk is quite fragmented (no defragger running), so I don't know if contiguous blocks would be an issue.

Q. Do we need to uncomment the variables specified above in modparams.dat and assign different values.

[Daniel Fernandez Illan]

Hi John

1Q. SYS$UPDATE:SWAPFILES use /NOCONTIGUOUS option to create SYSDUMP file (you does not need contiguous blocks)

2Q Pls. Seee SYSGEN HELP SYS_PARAMETERS DUMPSTYLE and appears a indication about values of this parameter:

5 - 14 Reserved for HP use only.

I think that you should not uncomment these values on MODPARAMS.DAT

Saludos.
Daniel.

[Hoff · Accepted solution]

<<<
Q. Can we simply run sys$update:swapfiles...
>>>

Yes.

>>>
The disk is quite fragmented...
<<<

It can be an issue in general, and it may or may not affect the creation of page or swap or dump files. Increasing fragmentation can and does have performance implications. It'll slow everything down. And increasingly severe fragmentation can eventually derail various file operations.

The core swap, page and dump files do not have to be contiguous.

BACKUP/IMAGE and (if you don't have a second disk) a restore), or a defragger (DFU has one), and I'd also look at setting up file extend sizes and related.

>>>
Q. Do we need to uncomment the variables specified above in modparams.dat and assign different values.
<<<

I usually set the pagefile, swapfile and dumpfile values to zero, and manage them myself. Potentially creating them with SWAPFILES, and sometimes manually. Setting them to zero tells AUTOGEN to keep its hands off the files, while setting those symbols to specific sizes tells AUTOGEN to select the specified size.

In no particular order...

DUMPSTYLE 9 is a selective, compressed dump. How much physical memory is in this box?

I'd likely set dumpstyle in modparams, if it's not already there.

Also poke around for ECOs, as there can be the occasional update to AUTOGEN or other core components.

Stephen Hoffman
HoffmanLabs

[Andy Bustamante]

Another option would be to configure the dump file on an alternate disk. See Volume 2 of the System Manager's Manual, http://h71000.www7.hp.com/doc/82FINAL/aa-pv5nj-tk/aa-pv5nj-tk.HTMl, Chapter 2. This would allow you to move on an plan to defragment the disk some time in the future.

Andy

[John A. Beard]

Sorry for the delay in getting back to you..the ususal 1001 things got in the way.

Just to further expand on our situation, the change we are looking at pertains to the sysdump file only, not the pagefile or swapfile 9both are fine and also have secondonary files defines on alternate disks).

We are not in the position at present to reallocate the dump file to another disk, so the size issues still remain for the system disk.

As for the projected size of the new file, I'm assuming that the size specified in the autogen report is based on capturing everything that would be in memory at the time of a crash.

The sysgen variable DUMPSTYLE is currently = 9, and i was wondering do I need to concern myself with it, or change it on the fly or set something in modparams.dat. Sorry, didn't get a chance to check up anything yet on the Help dumpstyle values.

[John A. Beard]

One other point at this stage regarding contiguous block allocation.... if you run swapfiles.com, does it check to make sure there are contiguous blocks available, or does it just do things on a best try basis.

[Hoff]

Again: the page, swap and dump files don't need to be contiguous.

If you should want them to be contiguous, you can use SYSGEN CREATE /CONTIGUOUS command. Directly. The SYSGEN CREATE command is what SWAPFILES uses for its purposes, too.

If you want to know about contiguous space or if you want defrag capabilities, do install the DFU tool off the OpenVMS Freeware, or off Jur's DFU site http://www.digiater.nl

As for your question, here's some DCL out of SYS$UPDATE:SWAPFILES.COM:

$SYSGEN CREATE PAGEFILE.SYS /SIZE='PAGEFILE' /NOCONTIG

The DCL procedure doesn't create the files as contiguous. The version of the DCL I'm looking at doesn't verify freespace, either, it just tosses the command at the disk.

[John A. Beard]

Thanks to all for your advice...we'll create the new file tomorrow morning