Operation and optimization of a Linux PC farm for physics analysis in the ZEUS experiment

The ZEUS experiment has migrated its reconstruction and analysis farms to a PC-based environment. More than one year of experience has been acquired with successful operation of an analysis farm designed for several hundred users. Specially designed software has been used to provide fast and reliable access to large amounts of data (30 TB in total). After the ongoing upgrade of the HERA luminosity, higher requirements will arise in terms of data storage capacity and throughput rate. The necessity of a bigger disk cache has led to consideration of solutions based on commodity technology. PC-based file servers are being tested as a cost-effective storage system. In this article we present the hardware and software solutions deployed and discuss their performance, scalability and maintenance issues.