Group and Window Mechanisms

Directory Server provides group and window mechanisms to optimize replication flow. The group mechanism enables you to specify that changes are sent in groups, rather than individually. The group size represents the maximum number of data modifications that can be bundled into a single update message. If the network connection appears to be the bottleneck for replication, increase the group size and check replication performance again. For information on configuring the group size, see Configuring Group Size in Sun Java System Directory Server Enterprise Edition 6.2 Administration Guide.

The window mechanism specifies that a certain number of update requests are sent to the consumer, without the supplier having to wait for an acknowledgement from the consumer before continuing. The window size represents the maximum number of update messages that can be sent without immediate acknowledgement from the consumer. It is more efficient to send many messages in quick succession instead of waiting for an acknowledgement after each one. Using the appropriate window size, you can eliminate the time replicas spend waiting for replication updates or acknowledgements to arrive. If your consumer replica is lagging behind the supplier, increase the window size to a higher value than the default, such as 100, and check replication performance again before making further adjustments. When the replication update rate is high and the time between updates is therefore small, even replicas connected by a LAN can benefit from a higher window size. For information on configuring the window size, see Configuring Window Size in Sun Java System Directory Server Enterprise Edition 6.2 Administration Guide.

Both the group and window mechanisms are based on change size. Therefore, optimizing replication performance with these mechanisms might be impractical if the size of your changes varies considerably. If the size of your changes is relatively constant, you can use the group and window mechanisms to optimize incremental and total updates.