CLUSTERS

Using multiple Cluster Replicators
If you have heavily used databases that consistently overload the Cluster Replicator with update requests, consider running multiple Cluster Replicators. When you run multiple Cluster Replicators on a server, they work simultaneously to replicate changes to other servers. If one Cluster Replicator is busy replicating changes to one database, a second Cluster Replicator can begin replicating changes to another database. By sharing the replication workload, multiple Cluster Replicators ensure that data updates are made quickly and databases stay tightly synchronized.

Determining how many Cluster Replicators to run

To determine how many cluster replicators to run, monitor the cluster replication statistics. For example, Replica.Cluster.WorkQueueDepth shows the number of modified databases that are waiting to be replicated. If the number of databases waiting is frequently greater than zero, consider adding one or more Cluster Replicators. However, the number of databases waiting to be replicated may also be greater than zero if you don't have enough network bandwidth to process the transactions fast enough. If this is the case, you should consider setting up a private LAN for your cluster. Also keep in mind that adding processors or memory to your server can enhance replication performance.

Replica.Cluster.SecondsOnQueue shows the number of seconds that the last database spent waiting in the replication queue before being replicated. Since the cluster replicator checks its queue every 15 seconds, this number should be under 15 during periods of light load. If this number is frequently higher than 30, you should consider adding one or more cluster replicators.

You should add one Cluster Replicator at a time until the cluster replication statistics are where you want them to be.

Starting multiple Cluster Replicators

You can configure IBM® Lotus® Domino™ to start multiple Cluster Replicators automatically each time the server starts, or you can start multiple Cluster Replicators for the current session only.

Starting multiple Clusters Replicators automatically at server startup

You can use the Domino Administrator or the Web Administrator to configure Domino to start multiple Cluster Replicators at server startup.

From the Domino Administrator
1. Click the Configuration tab.

2. In the Task pane, expand Server, and then click Configurations.

3. Do one of the following:

4. Click the NOTES.INI Settings tab.

5. Click Set/Modify Parameters.

6. In the Item field, select or enter CLUSTER_REPLICATORS.

7. In the Value field, enter the number of Cluster Replicators you want to run on this server.


8. Click Add, and then click OK.

9. Click Save & Close.

10. Restart the server so the setting takes effect.

From the Web Administrator
1. Click the Configuration tab.

2. In the Task pane, expand Server, and then click Configurations.

3. Do one of the following:

4. Click the NOTES.INI Settings tab.

5. Click Set/Modify Parameters.

6. In the Available Parameters box, click CLUSTER_REPLICATORS, and then click Add.

7. In the Value field, enter the number of Cluster Replicators you want to run on this server, and then click OK.


8. Click Save & Close.

9. Restart the server so the setting takes effect.

Starting multiple Cluster Replicators for the current session only

To run multiple Cluster Replicators for the current session only, do one of the following.

From the Domino Administrator or the Web Administrator
1. In the Server pane, expand All Servers or expand Clusters.

2. Select the server you want.

3. Click the Server - Status tab.

4. In the Task pane, do one of the following:

5. In the Tools pane, expand Task, and then click Start.

6. Select Cluster Replicator.

7. Click "Start Task" once for each Cluster Replicator you want to start, and then click Done.

From the server console
Send the following command from the server console once for each Cluster Replicator you want to start.


Each time you send this command, the server starts another Cluster Replicator.