How do I count the size that oracle ....

[Odd Olsson]

How do I count the size that oracle are suposed to use in sharedmemory.
I need to know this when I'm trying to decide how many db I can have in one server

//Regards
O.Olsson

[Rita C Workman]

Let's say that in the init.ora the DBA has set the amount of processes to 500 for a database and for another database (on the same box) he has set it's init.ora to 250 processes. You have a total of 750 processes you must now set your kernel parms to service. Here's one thread that mentions how to calc the semaphores (you can do a Search for more):
http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0x10ca6af52b04d5118fef0090279cd0f9,00.html

But remember...how many databases you can accomodate effectively is first dependent on how much memory and resources your server has !!!!!

Hope this gets you started,
Rita

[John Palmer]

Using sqlplus (Oracle 8i) or svrmgrl, you can connect and run the command:
show sga
This will output something like:
Total System Global Area 1520471060 bytes
Fixed Size 76820 bytes
Variable Size 240074752 bytes
Database Buffers 1279262720 bytes
Redo Buffers 1056768 bytes

The Total System Global Area is the amount of shared memeory that is used.

Oracle also outputs this information when you start the database.

Regards,
John

[Christian Gebhardt]

Hi

With 32-Bit-Oracle you can only use 2GB of physical Memory (Summary of all databases on one server).

Chris

[Steven E. Protter]

Here is a utility that is supposed to check your system configuration and let you know what shared memory kernel parms need to be prior to starting an installation.

If it helps, a few points please.

The utility can't check total physical memory, make sure you have at least 256 Meg manually.

This is from metalink.oracle.com

Enjoy.

[Odd Olsson]

I have 32-bit-Oracle on a 64-bit HP-UX server.
If I understands it right you can have a 4Tb shared Memory on a HP-UX 64-bit machine.
That means that I should be able to run 4000 DB with a SGA size of 1G on each. The max value 1.75 G (with right patch level)is for each 32-bit application not for the shared Memory.
Is this conclusion right ?
If I am wrong it means:
- You have two different shared Memory area one for 32-bit one for 64-bit aplications
or
- If I use 32-bit applications on a 64-bit Server the servers Shared Memory size are limited to 32-bit level size.

//This fun or ;-)

[Odd Olsson]

Or that all 32-bit applikation just have a 1.75G chunk inside the 64-bit shared Memory. And that 64-bit application can use the rest of the area.
Is that what you mean Christian?

//Regards

[Christian Gebhardt]

Hello Odd

If you don't use memory windows you are in fact limited to 1,75 GB shared memory in summary for all databases using Oracle 32-bit

I give you some postings to this theme. Searching for "memory windows oracle" will lead you to many other postings.

http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0xaacc91ccb36bd611abdb0090277a778c,00.html
http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0xd6fec6af36b7d5118ff10090279cd0f9,00.html

Chris

[Christian Gebhardt · Accepted solution]

Here's a pdf-documnet from HP, explaining memory windows.
Notice: The maximum size of SGA is limited to 3,75GB per 32-bit-database even if using memory windows

Chris

[Christian Gebhardt]

Here's a pdf-documnet from HP, explaining memory windows.
Notice: The maximum size of SGA is limited to 3,75GB per 32-bit-database even if using memory windows

Chris