The User-Level Remote Swap Library

This paper introduces the User-level Remote Swap Library, URSL, which enables memory-homogeneous Grid execution. This is obtained by letting the Grid infrastructure supply a remote memory bank to the connected resources. Insufficient memory at the contribution computer resource in a Grid is a major limitation when users seek to get high throughput in a Grid infrastructure, simply because a number of the available computers do not offer enough memory for the user job to run. URSL bypasses the lack of memory by offering the required memory as part of the Grid infrastructure in the form of a user-level swapping resource. A set of dedicated memory servers provide the additional memory that the computing resources then access remotely through the Grid infrastructure. Utilization of the extra memory is obtained without modifications to neither the operating system of the host resource nor the executed applications. The paper includes experiments that are made in an isolated Grid framework, and shows that the framework is fully operational, transparent and outperforms swapping to local disk in both the synthetic micro-benchmarks and in real-life scientific applications.