Fully redundant NAS with HAST + ucarp + ZFS + NFS

[Mickaël Canévet]

Hi,

I just installed 2 servers with FreeBSD 8.1rc2 and configured block 
level replication with HAST and fail-over with ucarp. It works like a 
charm, replication is pretty fast (35MB/s on my one disk system) and 
fail-over works great.

Now I would like to export some ZFS volumes over NFS (for the moment, 
but CIFS and iSCSI probably later).

When I mount a client over the VIP, fail-over works well for directory 
listing, but as soon as I try to do copy a file and switch node, the 
copy freeze.

I suppose it's because I have to share some kind of temporary directory 
also over my two server. On Linux, I would probably share /var/lib/nfs 
also, but on FreeBSD I'm a little bit lost.

Is it possible to solve my problem by sharing information over my two 
NFS servers ?

Will I have the same problem (or another one) with CIFS and/or iSCSI 
export ?

Thank you in advance for your answers, and a big bravo for all the 
developers that bring that kind of stuffs to us.

Mickaël