Network Considerations
The following replication issues affect the performance of your networks:
- The volume and typical size of data flowing over the network.
- The number of Subscribers to a particular Publisher.
- The speed and reliability of the line.
- The processing power of the Publisher, Distributor, and Subscribers.
If you are replicating over a slow link, the profiles for the agents involved in replication can be customized. For example, you can configure behavior such as the batch size, the polling interval, the timeout period, and the number of buffers available. The configuration options vary with the particular agent whose profile is being configured.
Network speed is often the most important issue when applying the initial snapshot. The volume of incremental data changes may be low, but the volume of data initially distributed may be high. Transferring the snapshot using a CD-ROM or tape device is one solution to this situation. Compressing the snapshot files can also help preserve network speed.
Knowing the processing power of the servers in your replication topology helps you decide whether to use remote agent activation. If you are using push subscriptions and there is greater processing power at the Subscriber, you may want to use remote agent activation so that the Distribution Agent or Merge Agent runs at the Subscriber rather than at the Distributor. If you are using pull subscriptions and there is greater processing power at the Distributor, you may want to use remote agent activation so that the Distribution Agent or Merge Agent runs at the Distributor rather than at the Subscriber.
You may also want to perform transformations on published data specific to individual Subscribers that discard some data at the Distributor. The transformation could discard the data before placing it on the network, and this could be a significant benefit for replication performance, especially if the network bandwidth is low.