Red Hat ENTERPRISE LINUX AS 2.1 - Guia de Instalação descarregar pdf (Página 67)

Configuring Very Large Memory (VLM)

use_indirect_data_buffers=true

db_block_size=8192

db_block_buffers=1048576

shared_pool_size=2831155200

Note that shmmax needs to be increased for shared_pool_size to fit into the System V shared

memory. In fact, it should be slightly larger than the SGA size. Since shared_pool_size is less than

3 GB in this example, shmmax does not need to be larger than 3GB. The 8 GB indirect buffer cache

will be in the RAM disk and hence it does not have to be accounted for in shmmax. On a 32 bit system

the shmmax kernel parameter cannot be larger than 4GB, see also Section 7.3, “Setting SHMALL

Parameter”.

In order to allow oracle processes to lock more memory into its address space for the VLM window

size, the ulimit parameter memlock must be changed for oracle. Ensure to set memlock in /etc/

security/limits.conf to 3145728:

oracle soft memlock 3145728

oracle hard memlock 3145728

$ ulimit -l

3145728

If it is not working after a ssh log in, then you may have to set the SSH parameter

UsePrivilegeSeparation, see Chapter 22, Setting Shell Limits for Your Oracle User.

If memlock is not set or too small, you will get error messages similar to this one:

ORA-27103: internal error

Linux Error: 11: Resource temporarily unavailable

Now try to start the database. Note the database start up can take a while. Also, the sqlplus banner

or show sga may not accurately reflect the actual SGA size in older Oracle versions.

The 8GB file for the database buffer cache can be seen in the ramfs shared memory file system:

$ ls -al /dev/shm

total 120

drwxr-xr-x 1 oracle dba 0 Nov 20 16:29 .

drwxr-xr-x 22 root root 118784 Nov 20 16:25 ..

-rw-r----- 1 oracle dba 8589934592 Nov 20 16:30 ora_orcl_458754

If the shared pool size is configured too large, you will get error messages similar to this one:

ORA-27103: internal error

Linux Error: 12: Cannot allocate memory

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Red Hat ENTERPRISE LINUX AS 2.1 - Guia de Instalação Página 67