On the Naming of Things

  • Simon Wilkinson, AuriStor Ltd

The directory structure casts a long shadow over AFS. It functions as a fileserver name store, a client side cache and as a transport format. Issues with the format cause some of the fundamental limitations of AFS - arbitrary limits on directory entries, lack of internationalisation and poor metadata performance.

This talk will examine each of these issues in turn - looking at scalability, lookup performance, and the thorny world of Unicode. We’ll look at the requirements for case insensitivity for Windows, and the unique approach to normalisation required for Mac OS.

We will present a new directory format building upon these existing foundations and discuss the challenges involved in transitioning live data over to a new format. We’ll talk about the need for a different paradigm as directory sizes grow, and examine the use of lookup and enumeration RPCs

Finally we will consider opportunities for future work that leverages the new directory format, including support for extended attributes.