NFS automounting. Stable for mail servers?

[Francisco Reyes]

Anyone successfully using an automounter in a busy Maildir mail hosting 
environment?

In particular any comments on stability and whether you are using the 
FreeBSD built in amd or the am-utils port.

Didn't find much on archives, but the little I found was individuals having 
problems.

A fellow ISP mentioned he tried the built in amd and had problems, but he 
tried on a pre 6.X environment (may have been 4.X).

Our setup has a number of front end mail machines accesing nfs servers.
To distribute the load we create directories like
/mail-server1
/mail-server2
/mail-server3 

Each of the front end machines mounts all the servers from fstab. Problem 
with that is that if loading from fstab if one of the nfs servers freezes 
the front end machines may have problems while trying to access the downed 
nfs server. Right now we only have a very small number of servers, but as 
the number of servers increase the more likely a single downed sever will 
affect all of the front end machines.