[CentOS] Nfs4 with kerberos freezing system

Hello,

I have a CentOS 5.2 server that exports /home on the local network for 2
users by secure nfs4 with kerberos krb5p. The clients are a notebook
and a desktop pc.
The following error is always reproducible on all clients. If running
the clients on high load, that means for example 5 firefox windows open
and connected with www pages from the internet, installing the new qt
development environmet on the nfs4 share from the 297 mb big
qt-sdk-linux-x86-opensource-2009.01.bin file and copy a 649 mb iso
image to the nfs4 share, the client is freenzing and a reboot is 
necessary. If running the clients on low load, than the system is
stable for hours.

In my opinion this is an error by an CentOS nfs package, cause this
problem is reproducible with different kernels, different desktop
environments and different clients. I don't think the error is caused
by the server hardware, cause if running the same nfs setting with nfs
version 3 and disabling nfs secure, the system is stable.

I have test this with
- latest CentOS 5.2 kernel and testing redhat kernel 2.6.18-133.el5
- kde and gnome
- different clients and hardware

Is anybody here successfully using nfs4/krb5p with CentOS 5.2?


regards
Olaf