Oracle7 Administrator's Reference for UNIX

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OFA Guidelines

OFA Rule 1: Naming Mount Points

Name all mount points that will hold site-specific data to match the pattern /pm, where:

p is a string constant
m is a unique fixed-length key used to distinguish each mount point
For example:

/u01 and /u02, or /disk01 and /disk02

Naming Mount Points for VLDBs

If you can guarantee that each disk drive will contain database files from exactly one application, and you have enough drives for each database to ensure that there will be no I/O bottleneck:

Name mount points matching the pattern /qdm, where:

q is a string denoting that Oracle data is to be stored there
d is the value of the db_name initdb_name.ora or configdb_name.ora parameter for the database
m is a unique fixed-length key that distinguishes one mount point for a given database from another.
For example: /ora/intl01 implies that data from the Oracle database intl is stored on this drive.

OFA Rule 2: Naming Home Directories

Name home directories matching the pattern /pm/h/u, where:

pm is a mount point name
h is selected from a small set of standard directory names
u is the name of the owner of the directory
For example: the Oracle Server software owner home directory might be /u01/app/oracle, and the Oracle Applications software owner home directory might be /u01/app/applmgr.

Placing all home directories at the same level in the UNIX file system makes it possible to put home directories on different mount points, yet still refer to the collection of login homes with a single pattern. The pattern /*/app/* can be used to refer to all application owner directories on the system.

OFA Rule 3: Referring to Pathnames

Refer to explicit pathnames only in files designed specifically to store them, such as /etc/passwd and /etc/oratab; refer to group memberships only in /etc/group.

OFA Rule 4: Software Directories

Store each version of the Oracle Server distribution software in a directory matching the pattern h/product/v, where:

h is the login home directory of the Oracle software owner
v is the version of the software
For example: /u01/app/oracle/product/7.2.3 names the start of the directory structure where the Oracle Server release 7.2.3 files are located. The environment variable ORACLE_HOME is set to this point in the directory structure for the active version of the Oracle7 Server.

OFA Rule 5: Administration Files

Store database administration files in the subdirectories of h/admin/d, where:

h is the Oracle software owner's home directory
d is the database db_name.
Valid subdirectories of h/admin/d are:

adhoc ad hoc SQL scripts for a given database
arch archived redo log files
adump audit files (Oracle7 audit feature--must clean out periodically) set audit_file_dest in configdb_name.ora to point here)
bdump background process trace files
cdump core dump files
create programs used to create the database
exp database export files
logbook files recording the status and history of the database
pfile instance parameter files
udump user SQL trace files

OFA Rule 6: Database Files

Name Oracle database files using the following patterns:

/pm/q/d/control.ctl control files
/pm/q/d/redon.log redo log files
/pm/q/d/tn.dbf data files
where:

pm is a mount point
q is a string distinguishing Oracle data from all other files
d is the db_name of the database
n is a fixed-length key for a given file type
t is an Oracle tablespace name.
Never store any file other than a control, redo log, or data file associated with database d in /pm/q/d.

/pm is the mount point name discussed earlier. The q layer is normally named ORACLE or oradata, satisfying OFA Requirement 10a. Naming the d layer db_name satisfies Requirement 10b. Requirements 10c and 10d are met by including the names for file types and tablespaces directly in the path.

OFA Rule 7: Separating Segments with Different Demands

Separate groups of segments with different lifespans, I/O request demands, and backup frequencies across different tablespaces.

For each Oracle database, create the following special tablespaces, in addition to those needed for application segments:

SYSTEM data dictionary segments only
TEMP temporary segments only
RBS rollback segments only
TOOLS general-purpose tools only
USERS miscellaneous user segments
This standard has proven itself at many sites. For example, because dictionary segments are never dropped, and because no other segments that can be dropped are allowed in the SYSTEM tablespace, this scheme guarantees that the SYSTEM tablespace will never require a rebuild due to tablespace free space fragmentation. Because no rollback segment is stored in any tablespace holding applications data, the administrator is never blocked from taking an applications tablespace offline for maintenance. Because segments are partitioned physically by type, the administrator can record and predict data growth rates without complicated tools.

OFA Rule 8: Naming Tablespaces

Name tablespaces descriptively using eight or fewer characters.

Although Oracle7 tablespace names can be thirty characters long, portable UNIX file names are restricted to fourteen characters. Recall that the recommended standard for a data file basename is tn.dbf, where t is a tablespace name and n is a two-digit string. The six-character n.dbf suffix leaves eight characters remaining for t.

Use descriptive names to allow the administrator to easily associate the name of a data file with the tablespace that uses it. For example, the names GLD and GLX might be used for the tablespaces storing General Ledger data and indices, respectively.

Resist the temptation to embed reminders of the word "tablespace" in your tablespace names. Tablespaces are distinguishable as such by their context, and their names do not need to convey information about their type.

OFA Rule 9: Raw Device Sizes

Choose a small set of standard sizes for all raw devices that may be used to store Oracle database files.

In general, standardizing on a single size is recommended. If a single size is used, raw files can be moved from one partition to another safely. The size should be small enough so that a fairly large number can be created, but large enough to be convenient.

For example, a 2 GB drive could be divided into 10 partitions of 200 MB each--a good balance between size and number. Any tablespace using raw devices should stripe them across several drives. If possible, the striping should be done with a logical volume manager.

OFA Rule 10: Administrative Home for Oracle Parallel Server

If you are using Oracle Parallel Server, select one node to act as Oracle administrative home for the cluster. The administrative home will house the administrative subtree defined [*]. Create subdirectories named for each instance accessing the database within the bdump, cdump, logbook, pfile, and udump directories of ~/admin/d. Ensure that the admin directory for the administrative home is mounted as the admin directory for every instance.

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