A Parallel Single Level Store systems (PSLS) integrates a shared virtual memory and a parallel file system. Managing globally the data, they provide programmers of scientific applications with the attractive shared memory programming model combined with a large and efficient file system in a cluster. In this paper, we present a cheap and efficient two-level checkpointing approach enabling a PSLS to tolerate failures. The first level checkpointing algorithm is very efficient and saves data in memory but requires a large amount of memory space. When memories are saturated, an alternative algorithm, saving a checkpoint on disks is implemented. Performance results present the impact of different variants of the checkpointing algorithms.