[Zope] suggestions for what to run in front of ZEO'ed zopes for failover?

[Roman Milner]

I'm wondering if anyone can suggest something good to run in front of
2 zopes talking to a zeo server - for failover and load balancing.  I
have been using a tool called 'balance' which works really well - but
for failover it only works if the socket to one of the zope servers
doesn't connect.

We occasionally have a situation where the socket will still answer
but the zope server hanges and never returns an answer.  So, I'm
looking for something with configurable timeouts on responses.  Does
any one know of anything like that?

Thanks,
^Roman