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Memory available for a single Oracle instance

Klaus Weyer
Occasional Visitor

Memory available for a single Oracle instance

Hi,

I think I know Oracle very well - but unfortunatly, I'm a complete rookie to HP-UX. Normaly we use Oracle-Databases with Windows NT or 2K. My Problem: I've got an Oracle 8.1.6i 64Bit on HP-UX 11.0 with 4 GBs of RAM. There's just on Instance on the System. When I try to set the amount of RAM for db_block_buffers to use more then about a 3rd of the total Memory, my Oracle replies "not enough Memory".
I think, it's because I can't give nearly the whole Memory to one Process - so that might by a simple Kernel-Parameter.
As I heard, there are Limitations about that on 32Bit-Systems, but not on 64Bit.
Can anybody help me?
5 REPLIES
A. Clay Stephenson
Acclaimed Contributor

Re: Memory available for a single Oracle instance

You probably simply need to increase the Kernel parameter maxdsiz_64. Since you are new to HP-UX, you should probably use SAM to reconfigure your kernel. It will step you through each of the actions and there is help for each tunable. The other thing you will almost ceratinly want to do is reduce dbc_max_pct from 50 to around 10 and dbc_min_pct to around 5.
If it ain't broke, I can fix that.
Carlos Fernandez Riera
Honored Contributor

Re: Memory available for a single Oracle instance

One usually very util thing is follow instalation procedure.

Another one is a good Unix admin.

You will recreate kernel to set maxdsiz_64 and many other parameters, semaphores, nfiles, nproc .....


Sorry... It is 03:00 AM here, and it seems i am tired.
unsupported
Roger Baptiste
Honored Contributor

Re: Memory available for a single Oracle instance

Hi,

Your kernel seems to need some resizing(increase) of its parameters. The default
kernel param values are low for handling
a oracle database instance. They need
to be increased and even oracle install
guides recommend it.

Your problem seems related with maxdsiz_64
value, though other parameters too would
help with some increase.

The best way to go about this would be
to run SAM and select the database parameter set, which is a set of kernel parms for
a database system. I don't remember the
exact name of the "set", but it can be
seen in SAM.

This would need a reboot of the box.

HTH
raj
Take it easy.
Wodisch
Honored Contributor

Re: Memory available for a single Oracle instance

Hello Klaus,

if you go for the "Monolithic Database Server" template then be sure to change the parameter "timeslice" back to "10", the "1" in the template is contra-productive (and plain silly).
When you apply the template you can easily see what parameters are changed, so make a note to remember those, as you will have to modify those individually later on, perhaps.

Good luck,
Wodisch
Deshpande Prashant
Honored Contributor

Re: Memory available for a single Oracle instance

Hi
Increasing following kernel parameters using SAM might help you.
maxdsize-64 and maxtsize-64.
The default for both is 64MB.

Thanks.
Prashant.
Take it as it comes.