Oracle9i Administrator's Reference
Release 2 (126.96.36.199.0) for UNIX Systems: AIX-Based Systems, Compaq Tru64 UNIX, HP 9000 Series HP-UX, Linux Intel, and Sun Solaris
Part No. A97297-01
This appendix contains the following tuning information for Oracle9i on Linux:
Oracle9i can allocate and use more than 4 GB of memory for the database buffer cache. This section describes the limitations and requirements of the extended buffer cache support on Linux.
See Also:Oracle9i Database Concepts for more information on the extend cache feature.
To use the extended buffer cache support on Linux, create an in-memory file system on the
/dev/shm mount point equal in size or larger than the amount of memory that you intend to use for the database buffer cache.
For example, for Linux to create an 8 GB
shmfs file system on the
/dev/shm mount point, enter the following as the
$ mount -t shm shmfs -o size=8g /dev/shm
When Oracle9i starts with the extended buffer cache feature enabled, it creates a file in the
/dev/shm directory that corresponds to the Oracle buffer cache.
Note:If an in-memory file system is already mounted on the
To enable the extended buffer cache feature, set the USE_INDIRECT_DATA_BUFFERS parameter to
true in the
ora file. Doing this allows Oracle9i to specify a larger buffer cache.
Do not use the following dynamic cache parameters while the extended cache feature is enabled:
If the extended cache feature is enabled, use the DB_BLOCK_BUFFERS parameter to specify the database cache size.
The following limitations apply to the extended buffer cache feature on Linux:
You cannot change the size of the buffer cache while the instance is running.
You cannot create or use tablespaces with non-standard block sizes.
See Also:Oracle9i SQL Reference for information on the standard block size used by the CREATE TABLE SPACE command.
Oracle9i supports kernel asynchronous I/O. This feature is disabled by default. If you are running Oracle9i on a system that supports kernel asynchronous I/O and that is certified by Oracle Corporation to use asynchronous I/O, perform the following steps to enable asynchronous I/O support:
root user, change directory to the
Enter the following commands:
$ make -f ins_rdbms.mk async_on
Note:If you receive the
By default, the DISK_ASYNCH_IO parameter in the
.ora file is set to
true to enable asynchronous I/O on raw devices. To enable asynchronous I/O on filesystem files:
Ensure that all Oracle data files are located on file systems that support asynchronous I/O.
Set the FILESYTEMIO_OPTIONS parameter in the
.ora file to