Provided that data is changed in only one ObjectServer
in a virtual pair, you can set up a bidirectional gateway for failback
operations. The operation is the same as for a unidirectional gateway,
but you need to configure different properties.
Restriction: Failback does not occur when the bidirectional
gateway connects to an ObjectServer that is not in a virtual pair.
For example, if you are using a bidirectional gateway to maintain
a backup ObjectServer, failback does not occur.
Procedure
To configure failback operations:
- In the backup ObjectServer, set the BackupObjectServer property to TRUE and restart the ObjectServer,
if required.
- Set the following properties in the gateway properties
file.
- If ObjectServer A has a backup ObjectServer, set the Gate.ObjectServerA.Failback property to TRUE.
- If ObjectServer B has a backup ObjectServer, set the ObjectServerGate.ObjectServerB.Failback property to TRUE
- To specify the frequency with which the gateway polls the
failed ObjectServer, set the Gate.ObjectServerA.FailbackTimeout and Gate.ObjectServerB.FailbackTimeout properties.
- To specify the Object Server pairs, set the Gate.ObjectServerA.Server property and the Gate.ObjectServerB.Server property to the virtual Object Server name.
Results
When the primary ObjectServer fails, the gateway fails over
to the backup ObjectServer without shutting down. When the gateway
is connected to a backup ObjectServer, it periodically polls for the
return of the primary ObjectServer. When the primary ObjectServer
is detected again, the gateway automatically fails back to the primary
ObjectServer.
Example
The following figure shows a sample failback operation
for a bidirectional gateway.
Figure 1. Bidirectional ObjectServer Gateway
What to do next
After you edit the properties file, restart the gateway.
