: AWAIT: Efficient Overload Management for Busy Multi-tier Web Services under Bursty Workloads Lei Lu, Ludmila Cherkasova, Vittoria de Nitto Persone, Ningfang Mi, Evgenia Smirni HP Laboratories HPL-2010-65 Multi-tier systems, admission control, overload, burstiness, Index of dispersion, performance evaluation The problem of service differentiation and admission control in web services that utilize a multi-tier architecture is more challenging than in a single-tiered one, especially in the presence of bursty conditions, i.e., when arrivals of user web sessions to the system are characterized by temporal surges in their arrival intensities and demands. We demonstrate that classic techniques for a session based admission control that are triggered by threshold violations are ineffective under bursty workload conditions, as user-perceived performance metrics rapidly and dramatically deteriorate, inadvertently leading the system to reject requests from already accepted user sessions, re...