It has a lot of great overview information, benchmarks, and interesting insight into ChunkFS, NILFS, btrfs, ext4, Reiser4, and ZFS.
I’ve been interested in how people are tackling the fsck problem which is one of the things he discusses. In my mind, it is already pain enough regardless of where it’s heading. The problem is also relevant to virtualization and grid computing. If you’re persisting and reusing VMs (not using the copy+throwaway model), the filesystems inside the VM are going to fsck eventually. Perhaps you have some timeout code in the meta-client layer that will only tolerate a certain wait for the VM to boot and report on its status somehow (perhaps using workspace contextualization technology). Because of the possible fsck delay you wouldn’t want to set this timeout very low (where it’s useful) unless you disabled filesystem checking which is not a great idea. A fsck friendly filesystem might become a popular VM choice? I’ll surely use a stable one for my local VMs and laptop.