LDFS: A Fault-Tolerant Local Disk-Based File System for Mobile Agents

A local disk-based file system, LDFS, is an attractive way to speed up distributed applications. Local file access is much faster than accessing data on remote file servers through the network. LDFS is also scalable, as it does not rely on centralized file servers, and it exploits already existing resources (local disks) to provide storage. However, since individual workstations are less reliable and less available than file servers, LDFS must be made fault tolerant. We present an approach that integrates the LDFS with the distributed application. This is particularly suitable for mobile agent systems, because they can easily migrate to access remote files. LDFS avoids logging of individual file accesses, which are regenerated automatically from application messages. Our experiments show that the overhead of checkpointing with LDFS is generally smaller that with NFS, while access time to files decreases dramatically.