System Administration in UNIX - system, parameters, performance Oracle Tips by Burleson Consulting

System Administration in UNIX

Just as the Oracle database is controlled by the values of an initialization file, the UNIX operating system is controlled by several initialization files. These files control the configuration of the Oracle server and the amount of available resources for all tasks that run on the server. The UNIX initialization files control every aspect of the OS environment, and especially those that are related to Oracle performance.

1. The setting for the number of semaphores (2x Oracle processes)

2. The amount of swap disk (at least 2x Ram memory)

3. The configuration of the mount points for the disks

4. The amount of available RAM memory

Most of the UNIX control facilities are beyond the scope of this text, but it is noteworthy that many of the UNIX system parameters have a direct impact on the performance of the Oracle database. Let’s take a closer look at those UNIX control files that impact Oracle.
(3) The UNIX /etc/system file
The /etc/system file control the setting for numerous UNIX kernel parameters. These parameters have a direct impact on the performance of the Oracle database. At Oracle installation time, the OS-specific installation manual directs the Oracle DBA to the appropriate settings for many of the kernel parameters.

Here is a typical /etc/system file for an Oracle server:

root> cat /etc/system
set shmsys:shminfo_shmmax=4294967295
set shmsys:shminfo_shmmin=1
set shmsys:shminfo_shmseg=10
set semsys:seminfo_semmni=24000
set semsys:seminfo_semmsl=100
set semsys:seminfo_semmns=24000
set semsys:seminfo_semopm=100
set semsys:seminfo_semvmx=32767
set tcp:tcp_conn_hash_size=4096

The above is an excerpt from the "Oracle9i UNIX Administration Handbook" by Oracle press, authored by Donald K. Burleson.