Using Guaranteed Delivery with Clustering
The guaranteed delivery capabilities of the webMethods Integration Server ensure guaranteed one-time execution of services. Guaranteed delivery ensures the following:
Requests from the client to execute services are delivered to the server.
Services are executed once, and only once.
Responses from the execution of services are delivered to the client.
In a clustered environment, if the Integration Server on which the service is running becomes unavailable, the client retries the service on another Integration Server in the cluster. However, to make sure a request will run if it fails on every server in the cluster, you must configure your Integration Servers to use guaranteed delivery. In addition, as in an unclustered environment, you must use guaranteed delivery to prevent a service from executing more than once. For more information about guaranteed delivery, refer to webMethods Integration Server Administrator’s Guide. For more information about developing services that use guaranteed delivery, refer to the Guaranteed Delivery Developer’s Guide.
When you use webMethods Integration Server clustering, guaranteed delivery stores information about requests for all the servers in the cluster in a shared, centrally located database. Because the information is stored centrally, guaranteed delivery uses a locking mechanism to synchronize updates to the database.
Attempts to update the database might time out. As a result, the server may require several attempts to complete a request. You can limit how long a cluster server sleeps between attempts to place an update lock on the database. In addition, you can set a maximum time limit after which the server overrides a lock on the database held by a non-responsive server in order to complete the update.
To configure cluster database locking
1. Open the Integration Server Administrator if it is not already open.
2. In the Settings menu of the Navigation panel, click Extended.
The server displays a screen that lists configuration properties specified in the server.cnf file.
3. To set how long a cluster server waits between attempts to place an update lock, locate the watt.server.tx.cluster.lockTimeoutMillis parameter. If this parameter does not exist, add it. Set it as follows:
Set this parameter: | To specify |
watt.server.tx.cluster. lockTimeoutMillis
| The number of milliseconds a cluster server waits between requests to place an update lock. |
4. To set how long a cluster server will wait before overriding a lock, locate the watt.server.tx.cluster.lockBreakSecs parameter. If this parameter does not exist, add it. Set it as follows:
Set this parameter: | To specify |
watt.server.tx.cluster. lockBreakSecs
| The number of seconds a cluster server waits before overriding a lock. |
For more information about using the Extended Settings screen to configure the Integration Server, see webMethods Integration Server Administrator’s Guide.
5. Click Save Changes.
6. Restart the server to put your changes into effect.
