Managing DPM Performance on a WAN

Published : September 27, 2005

Performance is a serious consideration when the DPM server and the file servers that it is protecting are connected by low-speed WAN links, particularly for resource-intensive jobs such as replica creation and consistency checks. For example, transferring a 20 GB volume across a 512 Kbps link would take at least 120 hours.

In this network configuration, you should enable compression for all protection groups. For replica creation of volumes larger than 5 GB, we recommend that you create the replica manually.

Replica creation cannot be interrupted and then restarted in the same manner as consistency checks. If it is not possible or practical to create the replica manually, and business needs prevent you from creating the replica across the network within the time available, you can use the following approach to work around this limitation:

  1. Create the protection group, specifying that DPM create the replica automatically over the network.

  2. When you see that replica creation is in process for the protection group, cancel the replica creation.

  3. Schedule a regular consistency check for the protection group, specifying an activity window that does not interfere with daily operations or affect network performance. 

DPM will finish creating the replicas as part of the consistency check process. When you use this approach, the data transfers more slowly than it does during replica creation, but the consistency check continues only during the hours for which it is configured, until it is complete.