Conception et évaluation d'un système de cache réparti adapté aux environnements virtualisés.

Some applications, like online sales servers, intensively use disk I/Os. Their performance is tightly coupled with I/Os efficiency. To speed up I/Os, operating systems use free memory to offer caching mechanisms. Several I/O intensive applications may require a large cache to perform well. However, nowadays resources are virtualized. In clouds, for instance, virtual machines (VMs) offer both isolation and flexibility. This is the foundation of cloud elasticity, but it induces a partitionning of the physical resources, including memory. This partitionning reduces the amount of available memory a VM can use for caching I/Os. In this paper, we propose PUMA, a tool that allows I/O intensive applications running on top of VMs to benefit of large caches. This is realized by providing a remote caching mechanism that provides the ability for any VM to extend its cache using the memory of other VMs located either in the same or in a different host. PUMA can increase application performance up to 9 times. [ABSTRACT FROM AUTHOR]