Specifying the Path for the New Data File (SAP Library - SAP Database Guide: Oracle (BC-DB-ORA-DBA))

Specifying the Path for the New Data File

Use

When you are using SAPDBA for Oracle to extend an existing tablespace or create a new tablespace – both of which involve adding a data file – you can specify a different path for the new data file. SAPDBA suggests a path for the data file, but this section tells you how to specify a different path if required.

Prerequisites

You can enter a different directory path for the new data file if the standard directory does not have enough storage space for the file. You can create the file in a file system that has sufficient space.

Recommendation

We generally recommend for performance reasons that you store data files and redo log files on different disks. For more information, see Organizing Disk Storage.

The following example shows how SAPDBA specifies the name of the data file:

Example

You are adding a third data file to tablespace PSAPDOCUD in the SAP database C11. PSAPDOCUD currently consists of the following files:

/oracle/C11/sapdata1/docud_1/docud.data1
/oracle/C11/sapdata2/docud_2/docud.data2

SAPDBA suggests /oracle/C11/sapdata2 for the new data file, and creates a subdirectory docud_3 , in which the file is created with name docud.data3 .

Therefore, the complete new file name is:

/oracle/C11/sapdata2/docud_3/docud.data3 .

SAPDBA only allows you to change the directory path, /oracle/C11/sapdata2/ in the above example. You cannot change the final part of the name, /docud_3/docud.data3 in the above example.

Procedure

If you are working with file systems, choose a new path in one of the following ways:

Using a different sapdata directory

You can create the file in a different standard directory, sapdata<n> . The directory must already exist and should be stored in a file system other than the one suggested by SAPDBA.

SAPDBA creates the new data file in the directory that you entered. It does not create a symbolic link from the directory it recommended.

Note that specifying a different directory might result in competing I/O accesses, which can reduce the performance of your system.

Using a non-standard path

You can create the file under a path which does not correspond to the SAP standard.

For example, you have set up and mounted a disk for data files. Therefore, new files must be added under path /usr/newdisk and not under the standard path.

SAPDBA then performs the following tasks:

It creates a subdirectory <tablespace name>_<file number> in the new directory /usr/newdisk , which you specified.

It creates a symbolic link between the SAPDBA default directory (for example, /oracle/C11/sapdata2/<tablespace name>_<file number>) and the new subdirectory /usr/newdisk .

It creates a file <tablespace name>.data<file number> in the new subdirectory.

The symbolic link is transparent in the Data Dictionary of the database. The Data Dictionary recognizes only that the file exists in the standard SAP directory.

If you are working with raw devices, SAPDBA behaves as described above in the section "Using a non-standard path". The symbolic link is set from <SAPDATA_HOME>/sapraw to the corresponding raw device. The file <tablespace-name>.data<file number> does not have to be created. See also Raw Devices and SAPDBA.