[OpenAFS] looking for a dfs on linux

[Octave]

Hello,
I have lot of servers (400 boxies) with lot of free space. 
What I am looking for is to use all this space. Of cource 
NFS would be a solution, but the problem of NFS is when 1 
server is down, all is down. There is no way to make 
High-Availability file system :/ For exemple (maybe it is
stupid but it is only for exemple) the best solution that 
I imagine would be a file system working with 3 serveurs like 
RAID-5 (1 server is down, all works). when the failed server
is back, the datas are recontructed.

Do you know if a file system (AFS ?) can do it ? Or works
with failed servers ?

Thanks in advance.
Octave