SESDCN can be restarted on the computer on which SESDCN was originally started (the cold-start computer) or on a different computer, the backup computer.
To restart an SESDCN on a backup computer, the whole SESDCN configuration must be on the restart computer.
You must therefore move all the components of this configuration to the backup computer. These can be:
application programs
SESDCNs
DBHs
the SES.DLGc backup file
DBH-specific files
The DBHs involved must be able to access all the databases assigned to them. All the required tasks must be restartable on the new computer.
Updating the distribution rules
If the SESDCN restart is executed on a backup computer, the location of the restart configuration in the network changes for the other configurations. The master DCN of the restart configuration therefore automatically replaces the name of the original computer with the name of the backup computer in the distribution rules of the remote computers known and accessible to it. This ensures that communication is still possible with the configurations on these machines.
If not all the remote computers in the network are accessible to the master DCN at the time of the SESDCN restart, the master DCN cannot change all the distribution rules automatically. In this case, you have to update the distribution-rule entries yourself using the MODIFY-DISTRIBUTION-RULE-ENTRY administration statement (see "MODIFY-DISTRIBUTION-RULE-ENTRY").
If several configurations execute their SESDCN restart on a backup computer after a crash, the associated master DCNs again cannot update all the distribution rules. They can update the distribution rules of configurations that have remained in the same position. They are accessible, but not those of configurations that have moved to another computer. In this case too, you have to update some of the distribution-rule entries manually using the MODIFY-DISTRIBUTION-RULE-ENTRY administration statement.
The master DCN updates the distribution rules only in the memory pool and the log file. Any input files that exist are not affected.