It is extremely difficult to keep up with all the filesystems being developed for Linux these days. Clearly, so much activity represents an understanding that the current filesystems do not address the needs of users. However, as is all too often the case, development is extremely fragmented with very small groups each trying to build the 1 true filesystem and thus each effort taking longer than a collaborative project.
What I want from a filesystem: snapshots, replication (local, aka RAID and network), checksums (at least optionally), compression (at least optionally), and some basic intelligence such as when a checksum fails and replication is used to get the data from another replica. Yes, fast error recovery and good performance are important too.
So what have we got right now:
- zfs-fuse – an interesting option, has most features I’m looking for except network replication, but definitely questionable reliability due to small size of project
- btrfs – also looking good in terms of features but small development and way behind schedule. no idea when it will be ready for production
- nilfs – small development team and small user base, does have checksums and snapshots but that’s it
- glusterfs – network and local replication but no snapshots, compression, or checksums at this time
- ceph – looks to have all features by adding network replication over btrfs, but who knows when it will be ready, or when btrfs will be ready
- hammer – dragonflybsd filesystem that has a read-only port on linux, no further development scheduled
- xtreemfs – has checksums and network replication but snapshots scheduled for the 2.0 release
- tux3 – dead
- crfs – dead
- pohmelfs – not enough info
- gfarm – haven’t seriously researched
So, what’s a sysadmin to due? Abandon Linux for OpenSolaris or Nexenta? I am thinking of giving nilfs another chance. I know it has checksums but I have no idea what happens when a checksum is wrong. It would be interesting to put nilfs on a raid 1 md setup and then trash one of the disks to see how it handles it. It would be nice to run zfs-fuse through the same test as this is the test zfs has excelled at for some years now.