- parallel read/write to multiple disk in RAID5 in btrfs (speed!, specially when multiple reading/writing userspace processes on btrfs which contains 10+ disks)
- pull back multi-path mgmt at FibreChannel driver level in kernel (WTF userspace need to know that scsi device have multiple path, userspace just get device and use it, rest is kernel work to handle, IMHO)
- throw out interface teaming (bonding is more that good, long time used in production, with VLAN tagging. 0 problems
p.s. you ask for Linux, not GNU Linux. Right?
The computer is to the information industry roughly what the central power station is to the electrical industry. -- Peter Drucker