VisageFS Translucent Directories: Efficient Posix Consistencies for Wide-Area Workflows

Abstract

One of the key challenges related to the grid environment is to efficiently use the storage resources of compute nodes. Therefore, we have developed the ViSaGe solution which features VisageFS -a POSIX-compliant wide-area file system, VCCC -a distributed lock mechanism, and VRT -a storage virtualisation layer.In this paper, we present the VisageFS translucent directory property which enables a dynamic, transparent and efficient use of local storage by means of hierarchical POSIX consistencies. Nodes that access a translucent enabled shared-directory will see different contents according to the site or node-level POSIX consistency. Thereafter, one of the various reconciliation modes re-enables the grid-level Posix consistency. Our "nevermind" mode does it in constant time.