  The Vera C. Rubin Observatory, currently in construction in Chile, will start
performing the Legacy Survey of Space and Time (LSST) in 2025 for 10 years. Its
8.4-meter telescope will survey the southern sky in less than 4 nights in six
optical bands, and repeatedly generate about 2 000 exposures per night,
corresponding to a data volume of about 20 TiB every night. Three data
facilities are preparing to contribute to the production of the annual data
releases: the US Data Facility will process 35% of the raw data, the UK data
facility will process 25% of the raw data and the French data facility,
operated by CC-IN2P3, will locally process the remaining 40% of the raw data.
In the context of the Data Preview 0.2 (DP0.2), the Data Release Production
pipelines have been executed on the DC-2 simulated dataset (generated by the
Dark Energy Science Collaboration, DESC). This dataset includes 20 000
simulated exposures, representing 300 square degrees of Rubin images with a
typical depth of 5 years. DP0.2 ran at the Interim Data Facility (based on
Google cloud), and the full exercise was independently replicated at CC-IN2P3.
During this exercise, 3 PiB of data and more than 200 million files were
produced. In this contribution we will present a detailed description of the
system that we set up to perform this processing campaign using CC-IN2P3's
computing and storage infrastructure. Several topics will be addressed:
workflow generation and execution, batch job submission, memory and I/O
requirements, etc. We will focus on the issues that arose during this campaign
and how we addressed them and will present some perspectives after this
exercise.
