Extending a Dbspace Without SAPDBA (SAP Library - SAP Database Guide: Informix (BC-DB-INF-DBA))

Extending a Dbspace Without SAPDBA

Use

This section describes how you can extend a dbspace of your Informix database by adding a new chunk using the Informix tool onspaces , that is, without using SAPDBA. You need to extend a dbspace when it is full or will soon be full. For more information, see Extension of a Dbspace.

Recommendation

SAP recommends you to extend a dbspace by Adding a Chunk with SAPDBA, because it is automated and easier to use than the procedure below. SAPDBA helps you locate free disk space and automatically adds a mirror chunk if the dbspace is mirrored.

Prerequisites

Before adding a chunk, make sure that it does not cause the maximum number of chunks allowed in your configuration to be exceeded. The maximum number of chunks is specified by the CHUNKS parameter in the ONCONFIG file. You can view this file by Listing System Information with SAPDBA.

If you add a chunk to a mirrored dbspace, you must also add a mirror chunk.

Caution

If you are manually extending a dbspace or creating a new one, do not allocate chunks where the sum of the offset plus the chunk size is larger than 2 GB, because this leads to severe problems. Refer to SAP Notes 34722 and 28335. This is one reason why SAP recommends that you add a chunk in SAPDBA, because it prevents you allocating chunks larger than 2 GB.

If you allocate raw devices (UNIX) or NTFS files (NT) with a maximum size of 2 GB, as recommended in the installation documentation, then you are even less likely to make this mistake with chunks.

Procedure

Enter a command like the following from the command line:

$ onspaces -a psappool -p /.../data3 -o 12 -s 10000

This example for UNIX adds a 10 MB chunk to the dbspace psappool .

The parameters are as follows:

Parameter	Meaning
a	Name of the dbspace to be extended
p	Path to a raw device link or NTFS file where sufficient disk space is available
o	Offset in KB
s	Size in KB

Note

To avoid problems on UNIX systems, SAP recommends that you specify an offset of 12 KB for the first chunk on a raw device. However, cooked files can have an offset of zero. For more information, see the Informix documentation.

See also:

Informix documentation at http://www.informix.com