fastcgi_buffers and fastcgi_buffer_size Q?

[izrodix]

Hi Guys,
after long googling and trying to find the right setup for nginx and
fastcgi
we came to three settings:
fastcgi_buffers, fastcgi_buffer_size and  fastcgi_read_timeout;

According to HttpFcgiModule manual the buffer size is equal to the size

of one buffer in fastcgi_buffers by default. Are this settings correct
because a few hours later we are still getting  BadGateway error ?

We are using Feebsd 8.2-STABLE amd64 jails and nginx from ports
sysctl hw.pagesize
hw.pagesize: 4096

fastcgi_connect_timeout 60;
fastcgi_send_timeout 20;
fastcgi_read_timeout 60;
fastcgi_buffers 512 4k;
fastcgi_buffer_size 4k;
fastcgi_busy_buffers_size 256k;
fastcgi_temp_file_write_size 256k;
fastcgi_intercept_errors on;
fastcgi_ignore_client_abort     off;

    limit_req_zone $binary_remote_addr zone=antiddosphp:10m rate=1r/s;  
                                                                        
                                                             
    limit_req_zone $binary_remote_addr zone=antiddos:10m rate=10r/s;    
                                                                        
                                                             
    open_file_cache             max=100000 inactive=40s;                
                                                                        
                                                             
    open_file_cache_valid       60s;                                    
                                                                        
                                                             
    open_file_cache_min_uses    2;                                      
                                                                        
                                                             
    open_file_cache_errors      on;  
client_max_body_size 150m;                                              
                                                                        
                                                         
                                                                        
                                                                        
                                                             
    ignore_invalid_headers   on;                                        
                                                                        
                                                             
    recursive_error_pages    on;                                        
                                                                        
                                                             
    sendfile    on;                                                     
                                                                        
                                                             
    tcp_nopush  on;                                                     
                                                                        
                                                             
    tcp_nodelay on;                                                     
                                                                        
                                                             
                                                                        
                                                                        
                                                             
    client_body_timeout   25;                                           
                                                                        
                                                             
    client_header_timeout 5;                                            
                                                                        
                                                             
    keepalive_timeout     25 5;                                         
                                                                        
                                                             
    send_timeout          25;                                           
                                                                        
                                                             
    reset_timedout_connection  on;        

Here is php-fpm settings
emergency_restart_threshold = 0
emergency_restart_interval = 0 
process_control_timeout=0                                               
                                                                        
                                           

pm=dynamic                                                              
                                                                        
                                                     
pm.max_children=65                                                      
                                                                        
                                               pm.start_servers=30      
                                                                        
                                                                        
                       pm.min_spare_servers=30                          
                                                                        
                                                                
pm.max_spare_servers=65                                                 
                                                                        
                                         pm.max_requests=10000          
                                                                        
                                                                        
          request_slowlog_timeout = 15s

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,169021,169021#msg-169021