The Historian Administrator can attach to either a local or remote Trend Historian. The Trend Historian supports Datasets with multiple paths to the data. The dataset name is defined with a primary path. This primary path is where the primary data is stored and new data will be logged into this path. A dataset can have a secondary path called the archive path that identifies the location for older trend data.
Older data is available to the viewer through the archive path.
This achieve path may be directed to a slower drive, or an alternative file server. Annotations cannot be added to data in the archive directory. The Canary Logger controls when the files are moved from the primary path into the archive. Files containing obsolete data can also be deleted automatically. The Canary Logger controls when the Trend Historian will purge old data from the system.