mongos?

if i have too mogos 

location /files/ {
           gridfs test
                  root_collection=fs
                  field=_id
                  type=objectid
                  user=qytest
                  pass=123456;
                  mongo 172.16.230.184:30000
                        172.16.230.183:30000;
                }

if i stop the mongos （172.16.230.183:30000） ，
it doesn't work
