Howdy,
 
I'm trying to setup a load balanced system with several web servers and one central log server. Currently I have syslog-ng running and pipe the output form apache to logger. This is all running locally on one box.  However, syslog-ng just randomly hangs and apache stop processing requests. I can restart apache and it still does not respond, but i can just restart syslog-ng and then it all starts working again.  Is syslog-ng designed to handle this kinda of load, around 3 million entries a day? I have been googling for hours and can only find some comments about log_fifo_size and reap_time in the options section? 
 
here is my current config, if that helps any
 
options { sync (0);
          time_reopen (10);
          log_fifo_size (1000);
          long_hostnames (off);
          use_dns (no);
          use_fqdn (no);
          create_dirs (no);
          keep_hostname (yes);
        };
destination d_http_access { file("/var/log/HTTP/$YEAR-$MONTH-$DAY/$YEAR-$MONTH-$DAY.accesslog" owner(root) group(root) perm(0600) dir_perm(0700) create_dirs(\
yes)); };
destination d_http_search { file("/var/log/HTTP/$YEAR-$MONTH-$DAY/$YEAR-$MONTH-$DAY.searchlog" owner(root) group(root) perm(0600) dir_perm(0700) create_dirs(\
yes)); };
destination d_http_error { file("/var/log/HTTP/$YEAR-$MONTH-$DAY/$YEAR-$MONTH-$DAY.errorlog" owner(root) group(root) perm(0600) dir_perm(0700) create_dirs(ye\
s)); };
filter f_http_access     { match("APACHE_ACCESS_LOG") and
                        not match("test.html"); };
filter f_http_search     { match("APACHE_ACCESS_LOG") and
                        match("/content/search"); };
filter f_http_error     { match("APACHE_ERR_LOG"); };
log { source(s_sys); filter(f_http_access); destination(d_http_access); };
#Log httpd search access logs
log { source(s_sys); filter(f_http_search); destination(d_http_search); };
#Log httpd error logs
log { source(s_sys); filter(f_http_error); destination(d_http_error); };
###################################################3
httpd.conf log line
CustomLog "|/usr/bin/logger -p local0.info -t APACHE_ACCESS_LOG" tracking