Hey Bryan, I loved your Fork Yeah! talk at USENIX. Everyone who's interested in the history and future of Solaris and ZFS should watch it: https://www.youtube.com/watch?v=-zRN7XLCRhc
I know it's a bit off topic but could you elaborate on the issues you see with BTRFS?
From an operations perspective, ZFS is a god-send. Correct me if I'm wrong, but AFAIK BTRFS lacks any significant quanta of improvement over ZFS, merely a "better licensed" non-invented-here mostly duplicated effort with a couple refinements that isn't nearly as well thought-out from the experience of ops folk.
- Online scrubbing rather than fsck, so there is little/no downtime if the filesystem were interrupted, i.e., datacenter power failure. fsck/raid rebuild of large filesystems can mean lengthy outages for users.
- "Always" consistent: Start writing the data of a transaction to unallocated space (or ZIL) and update metadata last.
- Greatly configurable block device layer:
* RAIDZ, RAIDZ2, RAIDZ3, mirror, concat ...
* ZIL (fs journal), L2ARC (cache) can be placed on different media or even combinations of media.
- Send & receive snapshots across the network.
I know it's a bit off topic but could you elaborate on the issues you see with BTRFS?