Description:
------------
memcache extension allows for failover (memcache.allow_failover = 1)
and can be used as a session handler (session.save_handler = memcache)

Unfortunately when failover happens a notice is thrown at session_start().

session_start() [function.session-start]: php_network_getaddresses: getaddrinfo failed: Name or service not known

Failover still works but the page is completed corrupted.
The manual is misleading: Quote 
"memcache.allow_failover boolean

    Whether to transparently failover to other servers on errors."

session_start does not deal with this so we can stay "transparent".