If the primary server within an HDR pair fails, the secondary server can be switched to standard mode by executing the onmode –d standard command. However, you must manually start Enterprise Replication by executing the cdr start command on that server. This is necessary to prevent Enterprise Replication from starting on both servers in an HDR pair. Table 15 shows how to switch the secondary server to standard mode.
| Step | On the Primary | On the Secondary |
|---|---|---|
| 1. | The server becomes unavailable. | |
| 2. |
onmode command onmode -d standard |
|
| 3. |
cdr command cdr start |
If you need to start the primary server while Enterprise Replication is running on the secondary server, use the oninit –D command to prevent Enterprise Replication and HDR from starting on the primary server.
If the problem has been resolved on the primary server and you wish to reestablish it as the primary server, then first stop Enterprise Replication on the secondary server. Otherwise, Enterprise Replication attempts to restart on the primary server while it is still active on the secondary server. Table 16 shows how to reestablish the primary server.
| Step | On the Primary | On the Secondary |
|---|---|---|
| 1. |
cdr command cdr stop |
|
| 2. |
onmode command onmode -s |
|
| 3. |
onmode command onmode -d secondary |
|
| 4. | oninit | |
| 5. |
cdr command cdr start |
If you want to split an active HDR pair into two stand-alone servers, then you must be careful to avoid Enterprise Replication starting on either server after they are split. To prevent Enterprise Replication and HDR from running, start the database servers with the oninit –D command.
If you remove a server from an HDR pair, use the cdr remove command to eliminate Enterprise Replication from that server. For example, the two HDR servers are being split and the secondary server is to be used for reporting purposes. After the report processing is complete, HDR can be reestablished. Table 17 shows how to remove a secondary server from HDR and Enterprise Replication.
| Step | On the Primary | On the Secondary |
|---|---|---|
| 1. |
onmode command onmode -d standard |
onmode command onmode -d standard |
| 2. |
cdr command cdr remove |
If the HDR primary server has problems communicating to its secondary server, Enterprise Replication is in a suspended state until one of the following actions is taken:
For more information on managing HDR servers, see the IBM Informix Dynamic Server Administrator's Guide.
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