Use delta compression

Delta compression on file transfers reduces network traffic by transferring only the sections of files that have been modified between revisions.


For delta optimization to be applied, the original revision of the file must have been fetched to, or saved from, the local work station. The greatest reduction in transfer time is for files that have modifications in only a few sections, and large continuous sections of unchanged content. Files that have widely dispersed multiple changes between revisions have a smaller improvement in transfer times.

Delta transfer is automatically enabled on a Dimensions CM server and all clients that connect to it, including:

  • Clients that run the dmcli command line, desktop client, and Eclipse and Visual Studio integrations.

  • Item library host, if different to the server.

  • Agents, including any used as library caches.

Prerequisites and limitations:

  • To use delta compression, personal library cache must be enabled.

  • Delta compression is used only for files larger than 32 KB.

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Manage delta transfers

To disable delta transfer, edit the Dimensions CM dm.cfg configuration file, and set the variable DM_DELTA_ENABLED to 0.

If you are using delta transfers with text files, add the following variable to the Dimensions CM dm.cfg configuration file on the server.


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Enable delta compression

Delta compression is disabled automatically for data formats that cannot be compressed. You can modify this setting for each format.

To change the delta compression setting:

  1. In the Administration Console, select Configuration Object Management > Data format & MIME types.

  2. Select a data format and click Edit.

  3. From the Compression level list, select the appropriate compression for the data format.

  4. Click OK.

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