Which other mature and stable filesystem can you recommend for such large storage?
Never had to deal with such a large filesystem, yet, but I'd try XFS on it.
Alternatively you can look at less supported filesystems such as BTRFS. Or even http://zfsonlinux.org/.
Since its for production, i would avoid both zfs and btrfs. But i guess there aren't many options available a.t.m. Best is to wait for btrfs to be production ready.
Wouldn't splitting the 11TB filesystem to smaller filesystems work ? You wont able able to avoid the fsck or disruption in service, but atleast you can bring up critical mounts faster.
- jb