The OpenArchive is a file based storage solution. The data is not stored in a database but in regular files. The Delft-FEWS FSS writes the data files directly to the archive data folder from an archive export workflow.
The timeseries are stored in NetCDF-files. Other data types are stored in xml or regular text files. In some cases, for example for security reasons, it is not possible for the Delft-FEWS FSS to write directly to the archive data folder. In that case the Delft-FEWS FSS should write to an intermediate folder and an copy script should copy the data files in the archive data folder.
To facilitate searching in the archive a catalogue is used. The catalogue is based on Elastic (https://www.elastic.co/), which is an open source tool for indexing data. The catalogue is populated by the so-called harvester.
The harvester scans the data folder to discover which data sets are available in the archive and updates the catalogue accordingly. THREDDS https://www.unidata.ucar.edu/software/thredds/current/tds/ , an open source software tool, is used to make the data accessible by Delft-FEWS and other third party applications. By using THREDDS the data can be downloaded by using HTTP. It addition THREDDS also supports protocols such as OpenDAP and WMS.
The Delft-FEWS PI-webservice can be used in combination with the OpenArchive. The seamless integration connects the Delft-FEWS data store with the archive. If data is requested from Delft-FEWS the data store will automatically retrieve the data from the OpenArchive if the data is expired from the FEWS data store.
