Open Data at CMS: Status and Plans

The CMS Experiment at the LHC has released many large datasets of proton-proton collision data as well as simulation to the public as part of its commitment to data preservation and open access. The collision data released totals around 2 fb$^{-1}$ at 7 TeV and nearly 12 fb$^{-1}$ at 8 TeV.Data preservation describes the efforts to not only preserve the data itself but the conditions in which it can be analyzed. This requires archiving and documenting information such as run environment and conditions and tools such as analysis software and workflows. Open access describes the efforts to share these tools and information with the public, including educators and researchers.These efforts present many challenges, partly due to the complexity and size of the CMS datasets and also to the knowledge required to make meaningful use of them. We describe here how we dealt with these challenges and the usage of CMS open data not only in public education and engagement but also in fundamental research. Furthermore we describe plans for future releases of data.