State of the Art: Where we are with the Ext3 filesystem
The ext2 and ext3 filesystems on Linux are used by a very large number of users. This is due to its reputation of dependability, robustness, backwards and forwards compatibility, rather than that of being the state of the art in filesystem technology. Over the last few years, however, there has been a significant amount of development effort towards making ext3 an outstanding filesystem, while retaining these crucial advantages. In this paper, we discuss those features that have been accepted in the mainline Linux 2.6 kernel, including directory indexing, block reservation, and online resizing. We also discuss those features that have been implemented but are yet to be incorporated into the mainline kernel: extent maps, delayed allocation, and multiple block allocation. We will then examine the performance improvements from Linux 2.4 ext3 filesystem to Linux 2.6 ext3 filesystem using industry-standard benchmarks features. Finally, we will touch upon some potential future work which is still under discussion by the ext2/3 developers.