State of the Art: Where we are with the Ext3 filesystem Mingming Cao, Theodore Y. Ts’o, Badari Pulavarty, Suparna Bhattacharya IBM Linux Technology Center {cmm, theotso, pbadari}@us.ibm.com,
[email protected] Andreas Dilger, Alex Tomas, Cluster Filesystem Inc.
[email protected],
[email protected] Abstract 1 Introduction Although the ext2 filesystem[4] was not the first filesystem used by Linux and while other filesystems have attempted to lay claim to be- ing the native Linux filesystem (for example, The ext2 and ext3 filesystems on Linux R are when Frank Xia attempted to rename xiafs to used by a very large number of users. This linuxfs), nevertheless most would consider the is due to its reputation of dependability, ro- ext2/3 filesystem as most deserving of this dis- bustness, backwards and forwards compatibil- tinction. Why is this? Why have so many sys- ity, rather than that of being the state of the tem administrations and users put their trust in art in filesystem technology. Over the last few the ext2/3 filesystem? years, however, there has been a significant amount of development effort towards making There are many possible explanations, includ- ext3 an outstanding filesystem, while retaining ing the fact that the filesystem has a large and these crucial advantages. In this paper, we dis- diverse developer community. However, in cuss those features that have been accepted in our opinion, robustness (even in the face of the mainline Linux 2.6 kernel, including direc- hardware-induced corruption) and backwards tory indexing, block reservation, and online re- compatibility are among the most important sizing.