topic Re: SHMMAX max memory in Operating System - HP-UX

SHMMAX max memory

rudy_3 — Fri, 31 Mar 2006 07:07:00 GMT

i have on my system 5 gb and i want to assign to sybase database 4 GB but i need to change SHMMAX to more then 4GB but it is not happening how can i make the memory usage bigger

Re: SHMMAX max memory

Peter Godron — Fri, 31 Mar 2006 07:12:39 GMT

rudy,
as you don't mention OS level, possible solution (11.11):
PHKL_30196

Re: SHMMAX max memory

RAC_1 — Fri, 31 Mar 2006 07:14:24 GMT

What version of OS? What version of Sybase 32/64 bit?

Re: SHMMAX max memory

rudy_3 — Fri, 31 Mar 2006 07:16:18 GMT

sorry about that
11.11

Re: SHMMAX max memory

rudy_3 — Fri, 31 Mar 2006 07:17:20 GMT

sybase 64 b

Re: SHMMAX max memory

Peter Godron — Fri, 31 Mar 2006 07:25:11 GMT

rudy,
another patch found:
PHKL_24032
seems there is whole raft of them out there

Re: SHMMAX max memory

rudy_3 — Fri, 31 Mar 2006 07:30:19 GMT

do u think a full system bk is needed or not really ??

Re: SHMMAX max memory

Peter Godron — Fri, 31 Mar 2006 07:35:15 GMT

rudy,
first ensure that these are the correct patches for your OS and that all the symtoms match. Then it depends on the criticality of the server, but normally you can back out a patch if you really need to.

Re: SHMMAX max memory

RAC_1 — Fri, 31 Mar 2006 07:37:48 GMT

Full system backup not required. But make sure that you are backing up old kernel.
cp /stand/vmunix /stand/vmunix.old
cp /stand/system /stand/system.old
cp -r /stand/dlkm /stand/dlkm.old

Re: SHMMAX max memory

rudy_3 — Fri, 31 Mar 2006 07:40:42 GMT

is it possible to bother you to send me the proper procedure of backing up the kernel and the system if you dont mind and what are the proper files to backup and the proper procedure to recover if you dont mind

Re: SHMMAX max memory

RAC_1 — Sat, 01 Apr 2006 04:10:16 GMT

Back up procedure is just about backing up old kernel files as mentioned above. Recovernig from old kernel will be as follows.

FROM ISL prompt, boot from old kernel.

hpux /stand/old_kernel_file_name.

Once you boot, you can move old files into place and start from there.

Re: SHMMAX max memory

rudy_3 — Sat, 01 Apr 2006 06:05:34 GMT

do u think any kmtune to do the settings or no
i applied patch 4302 but no luck i am searching for the other patch PHKL_30196
cant seem to find it

Re: SHMMAX max memory

Ninad_1 — Sat, 01 Apr 2006 06:32:26 GMT

Rudy,

What version of sybase database are you using ? Have you checked if there are restrictions in that version of sybase of how much max shared memory can be used. I am not famaliar with sybase, but I remember hearing from a DBA that some 8.x version of Oracle had a limitation of SGA size max limitation of 4 GB or something - so thought of suggesting you do check.

Regards,
Ninad

Re: SHMMAX max memory

RAC_1 — Sat, 01 Apr 2006 06:35:20 GMT

Patch is there.

http://www1.itrc.hp.com/service/patch/patchDetail.do?BC=patch.breadcrumb.main|patch.breadcrumb.pdb|patch.breadcrumb.search|&patchid=PHKL_30196&context=hpux:800:11:11

Also, how did you try setting shmmax to 4GB? Through SAM or through command line?

Re: SHMMAX max memory

Steven E. Protter — Sat, 01 Apr 2006 13:30:19 GMT

Shalom rudy,

You need to fully patch your system prior to configuring sybase.

Here is a SHMMAX rule of thumb.

The maximum usable setting for this paramter is 25 percent of memory. Memory in this case is defined as RAM plus swap.

Certain Oracle products require the SHMMAX setting to be set to 100% of physical RAM otherwise they won't install. The OS lets you do this and then proceeds to ignore settings higher than 25% of RAM.

The patche noted above permits you to set the settings for SHMMAX to where you need. SHMMAX is a dynamic kernel parameter with 11i and can be set without rebooting the system.

SEP

Re: SHMMAX max memory

rudy_3 — Mon, 03 Apr 2006 00:43:47 GMT

hi thanks to all but the patch PHKL_30196 has solved the case i only still have one question how did u find out about the patch that it was about the problem

thanks