Harvard University

The Log-structured File System (LFS), introduced in 1991 [8], has received much attention for its potential order-of-magnitude improvement in file system performance. Early research results [9] showed that small file performance could scale with processor speed and that cleaning costs could be kept low, allowing LFS to write at an effective bandwidth of 62 to 83 % of the maximum. Later work showed that the presence of synchronous disk operations could degrade performance by as much as 62 % and that cleaning overhead could become prohibitive in transaction processing workloads, reducing performance by as much as 40 % [10]. The same work showed that the addition of clustered reads and write