Database Reference
In-Depth Information
By defining directories with this structure it is ensured that the Oracle Universal Installer (OUI) will pick
up the OFA-compliant setup. Assuming a separate oracle and grid user you would continue by setting the
permissions as follows:
# chown grid:oinstall /u01/app/oraInventory/
# chmod 775 /u01/app/oraInventory/
# chown grid:oinstall /u01/app/
# chmod -R 775 /u01/app/
# chown -R oracle:oinstall /u01/app/oracle
# chmod -R 775 /u01/app/oracle
If you are planning on installing the database software only, there is no need for a grid user.
Setting session limits
The Pluggable Authentication Modules or PAM are a flexible way to authenticate users in a Unix environment. PAM
itself is “only” a framework-its functionality is implemented via modules. Such modules exist for many authentication
methods. When a user requests access to a Linux machine, the login process plays a crucial role in the process. Using
the services provided by the PAM library, it assesses that the user requesting a service (bash/ksh or other shell) is
actually who he claims to be. To that end, a multitude of authentication methods ranging from password to LDAP
can be employed, which are beyond the scope of this chapter. From an Oracle point of view, one property of the login
daemon is very important: it can assign limits to an individual user session.
The Oracle installation guide mandates that the following requirements are met:
•
The maximum number of open file descriptors must have a soft limit of 1024 and a hard limit
of 65536
•
The number of processes a user can create must be at least 2047 with a hard limit of 16384
•
A stack size (per process) of at least 10240KiB and at maximum of 32768 KiB
These settings are made in the
/etc/security/limits.conf
file, which unfortunately is still not documented
properly in the installation guides. In this file, every line follows this format (see man 5 limits.conf ):
domain type item value.
The relevant domain for the Oracle database installation is a username. The type can be either hard or soft, and
the item denotes which attribute is to be changed. To be more precise, we need at least amend the items “nofile,”
“nproc,” and “stack.” On the x86-64 platform, the values set by the oracle-rdbms-server-12cR1-preinstall RPM were
defined as follows:
[root@server1 ~]# cat /etc/security/limits.d/oracle-rdbms-server-12cR1-preinstall.conf \
>| grep ^oracle
oracle soft nofile 1024
oracle hard nofile 65536
oracle soft nproc 16384
oracle hard nproc 16384
oracle soft stack 10240
oracle hard stack 32768
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