  The Forschungszentrum Juelich has been hosting the German part of the LOFAR
archive since 2013. It is Germany's most extensive radio astronomy archive,
currently storing nearly 22 petabytes (PB) of data. Future radio telescopes are
expected to require a dramatic increase in long-term data storage. Here, we
take stock of the current data management of the Juelich LOFAR Data Archive,
describe the ingestion, the storage system, the export to the long-term
archive, and the request chain. We analysed the data availability over the last
10 years and searched for the underlying data access pattern and the energy
consumption of the process. We determine hardware-related limiting factors,
such as network bandwidth and cache pool availability and performance, and
software aspects, e.g. workflow adjustment and parameter tuning, as the main
data storage bottlenecks. By contrast, the challenge in providing the data from
the archive for the users lies in retrieving the data from the tape archive and
staging them. Building on this analysis, we suggest how to avoid/mitigate these
problems in the future and define the requirements for future even more
extensive long-term data archives.
