Help output is missing the Cluster options where the number of servers can be added as option:
Cluster options:
-s, --servers NUM Number of servers to start
-o, --only NUM Send command to only one server of the cluster
-C, --config FILE Load options from config file
--all [DIR] Send command to each config files in DIR
-O, --onebyone Restart the cluster one by one (only works with restart command)
-w, --wait NUM Maximum wait time for server to be started in seconds (use with -O)
considering this there are 2 options that gives you this issue:
- Windows does not support it
- Outdated gem version
update
https://github.com/macournoyer/thin/blob/master/lib/thin/runner.rb#L89
unless Thin.win? # Daemonizing not supported on Windows
update 2 another option that might help on windows:
Starting multiple instances of Thin Server on Windows with a batch script
read help start and try this
start /b thin start
and read again help start and play with other options