SGA_MAX_SIZE limit for Oracle 10g 32BIT on Linux Red Hat

Hi all,

We have a 32 Bit 10g database installed on Linux Redhat. The server has 4GB physical memory and only runs Oracle. Our SGA_MAX_SIZE parameter was set to 1.4GB, we need to increase this to 2GB. However when we tried to do restart the instance after the change, we got the following error:

ORA-27123: unable to attach to shared memory segment

Now i have checked the kernel parameters and these seem to be set fine, so i am wondering if i am hitting a limit for a 32 bit Oracle install?

Any advice will be much appreciated.

Thanks in advance,
Chucks

it turns out 32 bit cannot address more than 2GB memory space, you have seevral options, check them out on Metalink

You may be able to tweak your kernel parameters up to about 1.7 without any of the tricks in metalink, but in general, metalink tells you how to get to 2G. If you think you need something more, consider 64bit.

Raise SHMMAX in /etc/system or Lower SHARED_POOL_SIZE or lower
DB_BLOCK_BUFFERS accordingly.

This metalink Note may help you.
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