Ubuntu+Nginx packet loss / dropped upstream connections

[slowredbike]

Did you ever get a response to this...We are seeing the following:

no live upstreams while connecting to upstream....

we know the upstream servers are not crashing but are trying to determine
how/why they are being deemed as down.  The nginx gives no information on
this and the servers show no errors either.

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,244241,250288#msg-250288