Simulation of the cache hit rate for data readout at the Tokyo Tier-2 center

Abstract

The Tokyo Tier-2 center, which is located in the International Center for Elementary Particle Physics at the University of Tokyo, provides computing resources to the ATLAS experiment in the Worldwide LHC Computing Grid. In order to improve the I/O performance and scalability of file servers in the future system, a possibility of introducing a cache system using fast devices such as SSD is under discussion. Therefore, a simulation has been performed to understand the cache behavior using past data access logs at the center. This paper reports a method of the simulation and gives a discussion about its results.