Re: [BUG?] Maybe NFS bug since 2.6.37 on SPARC64

[Jim Rees <rees@umich.edu>]

Chuck Lever wrote:

  On Nov 4, 2011, at 9:20 AM, Jim Rees wrote:
  
  > As for a fix...  we're trying to move away from udp transport anyway.  Maybe
  > someone should figure out a way to get it to work with tcp?  I have zero
  > experience with nfs over udp, at least on linux.  Just for fun, have you
  > tried tcp transport (proto=tcp)?
  
  TCP is a real problem in this environment, because it deals poorly with
  NIC initialization timing issues.  UDP is still the best approach (as long
  as it is retransmitting appropriately).  To support TCP, ultimately what
  we need to do is to introduce serialization to make the kernel wait for
  the NIC to become ready before attempting network activity.

Agreed, but we're grasping at straws here, and this guy just wants it to
work.  It's something to try.

  > As we move toward nfs4 someone will have to give some thought to nfsroot.
  > It's hard to imagine we could put enough nfs4 cruft into the kernel (gssd,
  > idmapd) to make it work.
  
  A kernel-level basic id mapper is being considered.  That would allow
  NFSv4 with AUTH_SYS, if we can get the NIC problems squared away.

Actually I wonder if you could get by with auth_sys, no gss, and no id
mapping until you get to the point where the root is remounted by user land.