File Replication Service
File Replication Service |
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Use the following guidelines to help you optimize the performance of FRS.
The size and shape of a replica set, that is, the depth and breadth of its tree, can affect performance significantly. For example, if the replica set is fully meshed, with each member connected to every other member, the propagation of change orders for replicating files can impose a heavy burden on the network. To reduce unnecessary traffic, delete connections you do not actually need.
By default, Dfs creates a full-mesh topology. When you add a replica, Dfs creates a link between the new replica and every other member in the replica set and vice versa. To remove unwanted connections, use the Users and Computers administrative console. For guidelines on designing a Dfs topology, see "Distributed File System" in this book.
To spread out disk traffic, locate the FRS logs on a separate disk from the staging directory, the working directory, and the replicas themselves. (The working directory is the Ntfrs.jdb file.) This is especially important when logging with a high severity level. In fact, putting each of these areas on a separate disk drive gives the best replication performance because it distributes disk input/output (I/O).
To change the location where trace log files are stored, go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\NtFrs\Parameters, and edit the value of the Debug Log File entry. Before this change becomes effective, you must stop and restart FRS.
Caution
Do not use a registry editor to edit the registry directly unless you have no alternative. The registry editors bypass the standard safeguards provided by administrative tools. These safeguards prevent you from entering conflicting settings that might degrade performance or damage your system. Editing the registry directly can have serious, unexpected consequences that can prevent the system from starting and require that you reinstall Windows 2000. To configure or customize Windows 2000, use the programs in Control Panel or Microsoft Management Console (MMC) whenever possible.
If debugging replication problems is not a priority, you can disable logging to reduce disk traffic. Go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\NtFrs\Parameters, and change the value of the Debug Disable entry to 1.
A slow outbound partner can cause the staging directory to fill up. To avoid an interruption to FRS replication because the staging directory is full, construct replica connections that have comparable bandwidth for all outbound partners. It is also a good idea to balance the bandwidth for inbound and outbound connections.
Make sure the staging directory for replicated shares is large enough. The staging space limit governs the maximum amount of disk space that FRS can use to hold staging files. When this limit is reached, inbound replication pauses until space can be recovered by replicating one or more staging files to all outbound partners.
To adjust the size of the staging space, go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\NtFrs\Parameters, and edit the value of the Staging Space Limit in KB entry.
A replica set can include files that are stored offline in a tape library managed by Remote Storage. However, if you decide to deploy FRS and Remote Storage, remember that the overhead from replicating offline files can be substantial. For example, suppose a replica set has two members: Computer A and Computer B. Computer A uses Remote Storage to hold its replicated files whereas Computer B keeps its replicated files online. If Computer A is the initial master of the replica set, all of its files must be extracted from remote storage and replicated to Computer B when the latter is added to the replica set.
Frequent replication of data in the replicas can also be a burden for Computer A if the affected files must be retrieved from a tape. This is less of a concern when only a small subset of the replicated files, which are kept in disk storage on Computer A, are changed frequently by users.