Speaker
Description
For Phase-II of the Large Hadron Collider program, a dramatic increase in data quantity is expected due to increased pileup, higher experiment logging rates and a larger number of channels in the upgraded detector components. For Run-4, beginning in around 2030, and using the current computing model without software improvements, CMS estimates growth of an order of magnitude in computing resource needs compared with Run 3. We anticipate the demand to double again for Run-5, when the luminosity will reach the ultimate goals. This presentation discusses the construction of expected data transfer rates and the varied assumptions that contribute to the modeling. It further indicates where bottlenecks in our existing system may lie. The modeling considers the significant network traffic flows between major sites, as well as the expected peak read and write rates at tape endpoints. The results of these modeling exercises form the early planning stage for the upcoming WLCG “Data Challenge 2027”, scheduled for spring 2027. During this exercise the WLCG community will attempt to demonstrate the capability to handle typical Run-4 flows to the level of 50% of the estimated capacity.