Programming models for building large-scale distributed applications assist the developer in reasoning about consistency and distribution. However, many of the programming models for weak consistency, which promise the largest scalability gains, have little in the way of evaluation to demonstrate the promised scalability. We present an experience report on the implementation and largescale evaluation of one of these models, Lasp, originally presented at PPDP '15, which provides a declarative, functional programming style for distributed applications. We demonstrate the scalability of Lasp's prototype runtime implementation up to 1024 nodes in the Amazon cloud computing environment. It achieves high scalability by uniquely combining hybrid gossip with a programming model based on convergent computation. We report on the engineering challenges of this implementation and its evaluation, specifically related to operating research prototypes in a production cloud environment.H2020 - Horizon 2020 Framework Programme(609551)This work was partially funded by the SyncFree Project in the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement nº 609551, by the LightKone Project in the European Union Horizon 2020 Framework Programme for Research and Innovation (H2020/2014-2020), under grant agreement no 732505, by SMILES within project “TEC4Growth – Pervasive Intelligence, Enhancers and Proofs
of Concept with Industrial Impact/NORTE-01- 0145-FEDER-000020” - nanced by the North Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, and through the
European Regional Development Fund (ERDF). Chris is funded by the Erasmus Mundus Doctorate Programme under grant agreement no 2012-0030.info:eu-repo/semantics/publishedVersio
