Start Mirroring

Home | Previous Page | Next Page Utility Reference > onutil: Check, Define, and Modify Storage Objects > ALTER DBSPACE >

Start Mirroring

START MIRRORING Clause:

|--START MIRRORING--| Path Definition |-------------------------|

Path Definition:

   .-,-------------------------------------------------------------------------------------.
   V                                                                                       |
|----CHUNK--"--pathname--"--+----------------+--MIRROR--"--pathname--"--+----------------+-+--|
                            '-OFFSET--offset-'                          '-OFFSET--offset-'

Element	Purpose	Restrictions	Syntax
offset	The offset, in kilobytes, into the file or raw device to reach the chunk	Value must be greater than 0. See the chapter on managing disk space in the IBM Informix: Administrator's Guide.	Unsigned integer.
pathname	The file or raw device for the chunk	The chunk that you want to mirror must be an existing file or raw device. You can use a full pathname or a relative pathname. However, if you use a relative pathname, it must be relative to the directory that was the current directory when you initialized the database server.	Pathname must conform to the operating-system-specific rules for pathnames.

Usage

Use the ALTER DBSPACE onutil command with the START MIRRORING clause to mirror an existing dbspace. You can use the following keywords.

Keyword: Description
CHUNK: Specifies the file or raw device of the initial chunk of the dbspace that you want to mirror.
MIRROR: Specifies the file or raw device of the initial chunk of the dbspace that performs the mirroring. Use the MIRROR keyword when you want to mirror the new chunk.

Enabling Mirroring for a Chunk

Before you can enable mirroring, set the MIRROR parameter to 1 in the ONCONFIG file and restart the database server. Also, allocate disk space for the mirrored chunk. The following example shows how to use onutil ALTER DBSPACE to start mirroring for the root dbspace:

% onutil
1> ALTER DBSPACE rootdbs START MIRRORING
2> CHUNK "/ix/mywork/root_chunk.1"
3> MIRROR "/ix/mywork/mirr_chunk";