reverse proxy cache design

[roadfox]

at the moment we are running an active/standby reverse proxy
installation.
one virtual IP by keepalived.

it works great thanks to NGINX, but has the disantvantage of having an
empty cache on the standby proxy, so in case of a failover the cache
must first be filled up, which slows the proxy massively down.

i'm now thinking about adding the standby proxy the list of origin
servers, so i get something like this

proxy01 -> origin01
               -> origin02
               -> proxy02 -> origin01
                                   -> origin02
                   
this would make shure that proxy02's cache is filled to

will this make sense? can i configure proxy02 so he would directly
answer (direct server return)? or do i really need an loadbalancer in
front of the two ngingx proxys?

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,147654,147654#msg-147654