topic MAXDSIZ in Operating System - HP-UX

MAXDSIZ

Don Bentz — Mon, 02 Jul 2001 16:30:53 GMT

I have a K260 running HPUX 11.0 (32 BIT) with 2Gb of memory. I haven't been to the internals class yet, so I am wondering if somebody can tell me what the logical maximum size of this parameter can be. It is currently set at 512M.
Are there other parameters that will be affected by a change to this parameter? We are running Oracle 7.3.4 with an approximately 568M SGA.

Re: MAXDSIZ

Vincenzo Restuccia — Mon, 02 Jul 2001 16:34:52 GMT

Note that private memory-mapped files and shared-library data also occupy space in the dynamic storage region. This permits the possibility of conflict in the event you specify the highest possible values for maxdsiz or maxdsiz_64bit.

maxssiz
maxtsiz

See http://docs.hp.com/hpux/onlinedocs/os/KCparams.OverviewAll.html

Re: MAXDSIZ

Patrick Wallek — Mon, 02 Jul 2001 16:41:54 GMT

The link to the kernel parms that Vincenzo gave is a very useful one. Here the link to go directly to maxdsiz:

http://docs.hp.com/hpux/onlinedocs/os/KCparam.MaxDsiz.html

Re: MAXDSIZ

A. Clay Stephenson — Mon, 02 Jul 2001 16:55:21 GMT

Hi Don,

Normally 512M is plenty for maxdsiz. Unless a program has very large static arrays or does an extremely large amount amount of dynamic memory allocation via malloc(). Very large CAD or analysis program need large maxdsiz settings but very few other applications do. Oracle runs very comforftably at 512MB or even 256MB. The parameter you may need to change is shmmax since the SGA is allocated in shared memory.

Clay

Re: MAXDSIZ

Don Bentz — Mon, 02 Jul 2001 17:02:20 GMT

Thanks, everybody. Actually our shmmax is at 1 GB. The problem is that we have a process that loads a great deal of information into memory that has recently been modified so that a rather large cursor is being generated. It will probably continue to grow. I just wanted to know the maximum size. Thanks for the link. Very helpful although certainly some of the information is over my head right now, just looking at the configurable kernel parameters and their descriptions. I hope to gain a bit more understanding from the class July 30...