How much data is recorded during an observation and how it is transferred to the central processing facilities?

Depending on instrument setup, weather, position within the array, and other factors, a five-day observing campaign can produce about a Petabyte (PB) of raw data per observatory. The total amount of raw data recorded in April 2017 is about 3.5 PB. This data must be recorded to hard disks and manually transported to central processing facilities in Germany and the United States, as transferring it via the Internet would take considerable time. Approximately 5.5 PB data were recorded during the April 2018 observations. Future campaigns are expected to record up to 15 PB per year.

Data storage and processing enthusiasts may want to look up more details in this article.