Chapter 24. Creating Oracle Directories

For Oracle 10g you only need to create the directory for $ORACLE_BASE:
su - root
mkdir -p /u01/app/oracle
chown oracle.oinstall /u01/app/oracle
If you want to comply with Oracle's Optimal Flexible Architecture (OFA), then you do not want to place the database files in the /u01 directory but in another directory, file system or disk such as /u02:
su - root
mkdir -p /u02/oradata/orcl
chown oracle.oinstall /u02/oradata/orcl
In this example, "orcl" stands for the name of the database which will also be the name of the instance. This is typically the case for single instance databases.

24.1. Optimal Flexible Architecture (OFA) for 10g R1 (

The OFA standard is a guideline created by Oracle to ensure reliable Oracle installations. For Oracle 10g Database, the OFA recommended Oracle home path has changed.
The home path for the first 10g (10.1.0) database installation on a system would be:
If you would install a second Oracle 10g Database 10g (10.1.0) on the same system, the Oracle home directory should be as follows:
If the Oracle 10g software is not owned by the user oracle but by the user "oraowner", then the path of the Oracle home directory would be:
The standard directory name for Oracle 10g is "app":
Oracle recommends to use mount points such as /u01, /u02, and so on, complies with the OFA guidelines. But others can be used, for example:
The subtree for database files not stored in ASM disk groups should be named as follows:
The mount point /u01 should be used for the Oracle software only. /u02, /u03, /u04 and so on, should be used for the database files. The db_name represents the DB_NAME initialization parameter which is typically the same as the SID name for single instance databases.