The prototype of the Large Size Telescope (LST) of CTA, located at the Observatorio del Roque de Los Muchachos (ORM) on the Canary Island of La Palma, is presently going through its commissioning phase. A total of four LSTs, among others, will operate together at ORM constituting the CTA North site.
A computing center endowed with 1760 cores and several petabytes disk space is installed onsite and used to acquire, process, and analyze the data produced, around 3 TB/hour during operation. LSTOSA is a set of scripts written in python which connects the different steps of the analysis pipeline developed for the LSTs, called lstchain. It processes the data produced by the prototype in a semiautomatic way producing high-level data and quality plots including detailed provenance logs. Data are analyzed before the next observation night to aid in the commissioning procedure and debugging.