Designing a Replication Schedule

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Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2

When you use the Distributed File System snap-in to configure replication, FRS schedules replication to take place 24 hours a day, seven days a week. Whenever you copy a file to a target that participates in replication, or when an existing file in the replica set is changed, FRS replicates the entire file to the other targets using the connections specified in the replication topology. Continuous replication is advised only for environments that meet the following criteria:

  • The replica members are all connected by high-bandwidth connections, such as hub servers in a redundant hub and spoke topology.

  • The amount of data to be replicated is not so large that it interferes with the bandwidth required for other purposes during peak or off-peak hours.

  • The application whose data is being replicated needs rapid distribution of file changes, such as antivirus signature files or login scripts.

If your environment does not meet these criteria, plan to create a replication schedule so that data is replicated at night or during other times as appropriate. A replication schedule involves enabling and disabling replication so that it occurs at specified times on specified days. For example, you might schedule replication to occur beginning at 12:00 midnight and ending at 2:00 A.M. every day.

When determining the replication schedule, consider the following issues:

Amount of data to be replicated and the length of the replication window   Estimate the amount of data to be replicated so that you can choose a duration that is long enough to replicate all the data. In DFS namespaces, replication stops when the schedule window closes, and any remaining files are delayed until the next replication window opens. If you occasionally put a large amount of data into the replica set, FRS might take several replication periods to replicate all the data.

Amount of latency your organization can tolerate   If you plan to replicate data that changes frequently, consider the amount of latency that you can tolerate in keeping your targets synchronized and the amount of bandwidth that is consumed during replication.

Whether you want to stagger schedules   If you are using a redundant hub and spoke topology with several hubs, you can split the replication load among the hubs by staggering the schedule. An example of this schedule is described in "Example: An Organization Designs a Replication Strategy" later in this chapter.

For an Excel spreadsheet to assist you in documenting the replication schedule, see "FRS Configuration Worksheet" (Sdcfsv_2.xls) on the Windows Server 2003 Deployment Kit companion CD (or see "FRS Configuration Worksheet" on the Web at https://www.microsoft.com/reskit).