Use and change mirroring of chunks

Before you can add a mirror chunk, the disk space for that chunk must already be allocated on both the primary and secondary database servers. If you want to mirror a dbspace on one of the database servers in the replication pair, you must create mirror chunks for that dbspace on both database servers. For general information about allocating disk space, see Allocate disk space.

Do not set the MIRROR configuration parameter to 1 unless you are using mirroring.

You can perform disk-layout operations from the primary database server only. Thus, you can add or drop a mirror chunk only from the primary database server. A mirror chunk that you add to or drop from the primary database server is added to or dropped from the secondary database server as well. You must perform mirror recovery for the newly added mirror chunk on the secondary database server. For more information, see Recover a mirror chunk.

When you drop a chunk from the primary database server, HCL Informix® automatically drops the corresponding chunk on the secondary database server. This applies to both primary and mirror chunks.

When you turn mirroring off for a dbspace on the primary database server, Informix does not turn mirroring off for the corresponding dbspace on the secondary database server. To turn off mirroring for a dbspace on the secondary database server independent of the primary server, use onspaces -r. For more information about turning off mirroring, see End mirroring.

You can take down a mirror chunk or recover a mirror chunk on either the primary or secondary database server. These processes are transparent to HDR.


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