I am new to mongoDB. We have new installation with 2 sharded clusters. What I noticed that local db is 150G in size and all tables are empty. Repair database does not seems to me helped. I am sure something went wrong and I need to get a root cause of that.

autotrader 0.203125GB
local 156.001953125GB
rs0:PRIMARY> use local
switched to db local
rs0:PRIMARY> show tables
me
oplog.rs
replset.minvalid
slaves
startup_log
system.indexes
system.replset
rs0:PRIMARY> db.me.count()
1
rs0:PRIMARY> db.oplog.rs.count()
6
rs0:PRIMARY> db.replset.minvalid.count()
1
rs0:PRIMARY> db.slaves.count()
2
rs0:PRIMARY> db.startup_log.count()
6
rs0:PRIMARY> db.system.indexes.count()
4
rs0:PRIMARY> db.system.replset.count()
1
rs0:PRIMARY>