Title: Dynamic Asynchronous Weighted Replication

Speaker: Hasan Heydari, LASIGE – DI/FCUL

Date: March 22, 12h00

Where: FCUL, room C6.3.27

Abstract: The performance of distributed systems deployed on wide-area networks can be improved using weighted (majority) quorums instead of regular ones due to the performance diversity of the nodes. A significant limitation of weighted majority quorums is their reliance on static weights, which are inappropriate for systems subject to environmental changes. To overcome such a limitation, weighted majority quorums need mechanisms for reassigning weights over time according to the performance variations.

In this talk, we study the problem of node weight reassignment in asynchronous systems. We prove that solving such a problem is as hard as solving consensus, i.e., it cannot be implemented in asynchronous failure-prone distributed systems. This result is somewhat counter-intuitive, given the recent results showing two related problems — replica set reconfiguration and asset transfer — can be solved in asynchronous systems.

Bio:Hasan Heydari is a postdoctoral researcher at LASIGE. He did his Ph.D. in computer science and embedded systems at Université Toulouse III, Toulouse, France, in 2022. His main research interests include replication techniques, quorum systems, consensus, and blockchain.