mongod will start with --fastsync and --master, despite these options being a contradiction. The server will then silently not accept any connections - the logs show it having stopped at "no journal files present, no recovery needed". Supplying --fastsync and --master should error out with a message that these arguments are mutually exclusive.

db version v2.0.0-rc0, pdfile version 4.5
Thu Sep 1 14:41:28 git version: 8d4bf50111352cee5a4f1abf25b63442d6c45dc4

==== Example ====

/tmp/mongodb-linux-x86_64-2.0.0-rc0/bin > pgrep -lf mongo
17541 ./mongod --master --fastsync --dbpath /tmp/ --fork --logpath /tmp/md.log

/tmp/mongodb-linux-x86_64-2.0.0-rc0/bin > cat /tmp/md.log
Thu Sep 1 14:59:34 [initandlisten] MongoDB starting : pid=17630 port=27017 dbpath=/tmp/ master=1 64-bit host=XXXXXXXX
Thu Sep 1 14:59:34 [initandlisten] db version v2.0.0-rc0, pdfile version 4.5
Thu Sep 1 14:59:34 [initandlisten] git version: 8d4bf50111352cee5a4f1abf25b63442d6c45dc4
Thu Sep 1 14:59:34 [initandlisten] build info: Linux bs-linux64.10gen.cc 2.6.21.7-2.ec2.v1.2.fc8xen #1 SMP Fri Nov 20 17:48:28 EST 2009 x86_64 BOOST_LIB_VERSION=1_41
Thu Sep 1 14:59:34 [initandlisten] options:

{ dbpath: "/tmp/", fastsync: true, fork: true, logpath: "/tmp/md.log", master: true }

Thu Sep 1 14:59:34 [initandlisten] journal dir=/tmp/journal
Thu Sep 1 14:59:34 [initandlisten] recover : no journal files present, no recovery needed

/tmp/mongodb-linux-x86_64-2.0.0-rc0/bin > ./mongo
MongoDB shell version: 2.0.0-rc0
connecting to: test
Thu Sep 1 14:58:38 Error: couldn't connect to server 127.0.0.1 shell/mongo.js:84
exception: connect failed

/tmp/mongodb-linux-x86_64-2.0.0-rc0/bin > pkill mongo

/tmp/mongodb-linux-x86_64-2.0.0-rc0/bin > ./mongod --master --dbpath /tmp/ --fork --logpath /tmp/md.log
forked process: 17604
all output going to: /tmp/md.log

/tmp/mongodb-linux-x86_64-2.0.0-rc0/bin > cat /tmp/md.log
Thu Sep 1 15:00:00 [initandlisten] MongoDB starting : pid=17659 port=27017 dbpath=/tmp/ master=1 64-bit host=XXXXXXX
Thu Sep 1 15:00:00 [initandlisten] db version v2.0.0-rc0, pdfile version 4.5
Thu Sep 1 15:00:00 [initandlisten] git version: 8d4bf50111352cee5a4f1abf25b63442d6c45dc4
Thu Sep 1 15:00:00 [initandlisten] build info: Linux bs-linux64.10gen.cc 2.6.21.7-2.ec2.v1.2.fc8xen #1 SMP Fri Nov 20 17:48:28 EST 2009 x86_64 BOOST_LIB_VERSION=1_41
Thu Sep 1 15:00:00 [initandlisten] options:

{ dbpath: "/tmp/", fork: true, logpath: "/tmp/md.log", master: true }

Thu Sep 1 15:00:00 [initandlisten] journal dir=/tmp/journal
Thu Sep 1 15:00:00 [initandlisten] recover : no journal files present, no recovery needed
Thu Sep 1 15:00:00 [initandlisten] waiting for connections on port 27017
Thu Sep 1 15:00:00 [websvr] admin web console waiting for connections on port 28017

/tmp/mongodb-linux-x86_64-2.0.0-rc0/bin > ./mongo
MongoDB shell version: 2.0.0-rc0
connecting to: test
>
bye