We now describe the design and implementation of SSM, a lightweight session-state store. We make the following assumptions about the operating environment, which are typical of large-scale services [3]: a physically secure cluster interconnected by a commercially-available high-throughput, low-latency system area network (SAN); and an uninterruptible power supply to reduce the probability of a system-wide simultaneous hardware outages. The Java prototype consists of 872 semicolons and runs on the UC Berkeley Millennium Cluster, consisting of 42 IBM xSeries 330 1U rackmounted PCs, each running Linux 2.4.18 on Dual 1.0 GHz Intel Pentium III CPUs and 1.5GB ECC PC133 SDRAM, connected via Gigabit Ethernet.