I have seen some serious performance and some error messages with and mongrel_cluster.

First let's talk about the error messages.

server ~ / $ /etc/init.d/mongrel_cluster start
Starting all mongrel_clusters...
!!! Path to log file not valid: log/mongrel.8000.log
mongrel::start reported an error. Use mongrel_rails mongrel::start -h to get help.
!!! Path to log file not valid: log/mongrel.8001.log
mongrel::start reported an error. Use mongrel_rails mongrel::start -h to get help.
!!! Path to log file not valid: log/mongrel.8002.log
mongrel::start reported an error. Use mongrel_rails mongrel::start -h to get help.
server ~ / $

To correct this error simple edit /etc/mongrel_cluster/.yml and give the full path for log_file and pid_file

log_file: /opt/redmine/log/mongrel.log
pid_file: /opt/redmine/tmp/pids/mongrel.pid

Talking about performance. It happens that you have to reload several times the site before it gets shown in the . Reading some docs I figured out that it is good to edit the generated yml file.

server ~ / $ cat /etc/mongrel_cluster/redmine.yml
--- 
user: nginx
cwd: /opt/redmine/
log_file: /opt/redmine/log/mongrel.log
port: "8000"
environment: production
debug: false
group: nginx
address: 127.0.0.1
pid_file: /opt/redmine/tmp/pids/mongrel.pid
servers: 3
num_processors: 1024
timeout: 0
docroot: public