never mind. i figured this out. thx,by evuraan - Nginx Mailing List - English
Per http://wiki.nginx.org/NginxHttpUpstreamModule#.24upstream_cache_status, $upstream_cache_status appeared in 0.8.3. I run 0.8.47, and have in my conf: <snip> log_format cache '***$time_local ' 'Server : $upstream_addr ' 'Status: $upstream_cache_status ' 'Cache-Control: $upstream_http_cache_control 'by evuraan - Nginx Mailing List - English