Defining Shadow Replicates

A shadow replicate is a copy of an existing, or primary, replicate. Enterprise Replication uses shadow replicates to manage alter and repair operations on replicated tables. You must create a shadow replicate to perform a manual remastering of a replicate that was defined with the -n option. See Resynchronize data manually for information about how you can repair, or remaster, your replicated data. After creating the shadow replicate, the next step in manual remastering is to switch the primary replicate and the shadow replicate using the cdr swap shadow command.

You create a shadow replicate using the cdr define replicate command with the --mirrors option, as described in cdr define replicate.

When you define a shadow replicate, its state is always set to the same state as the primary replicate. If you change the state of the primary replicate, all its shadow replicates’ states are also changed to the same state.

You cannot delete a primary replicate if it has any shadow replicates defined. You must first delete the shadow replicates, and then the primary replicate.

You cannot modify a primary replicate (using the cdr modify replicate command) if it has any shadow replicates defined. Also, you cannot modify shadow replicates directly.

You cannot suspend or resume a primary replicate (using the cdr suspend replicate or cdr resume replicate command) if it has any shadow replicates defined. Also, you cannot suspend or resume shadow replicates directly. If the primary replicate and its shadow replicates are part of an exclusive replicate set, you can suspend or resume the entire replicate set using the cdr suspend replicate or cdr resume replicate command.

If the primary replicate is part of an exclusive replicate set, any shadow replicates you define are automatically added to that replicate set.

If you add a primary replicate to an exclusive replicate set, all its shadow replicates are also automatically added. If you delete a primary replicate from an exclusive replicate set, all its shadow replicates are also automatically deleted.