Django distributed memcached handling when server in cluster goes offline

[LiteWait]

I've got Django/memcached running in a 4 web server configuration on AWS.  In settings.py each web server has (of course) a list of all the IPs participating in the memcached cluster.  What I am noticing is when a server goes offline, all requests slow to a complete crawl presumably because Django/memcached is attempting to reference keys that has to the server that is down and is timing out.

Is this expected behavior?  If so how are others handling this?

Thanks.