mongorestore --drop -v
2014-11-25T09:19:44.307-0600	using default 'dump' directory
2014-11-25T09:19:44.309-0600	using write concern: w='1', j=false, fsync=false, wtimeout=0
2014-11-25T09:19:44.309-0600	building a list of dbs and collections to restore from dump dir
2014-11-25T09:19:44.309-0600	found collection ycsb.usertable bson to restore
2014-11-25T09:19:44.309-0600	found collection ycsb.usertable metadata to restore
2014-11-25T09:19:44.310-0600	reading metadata file from dump/ycsb/usertable.metadata.json
2014-11-25T09:19:44.310-0600	no collection options to restore
2014-11-25T09:19:44.310-0600	restoring ycsb.usertable from file dump/ycsb/usertable.bson
2014-11-25T09:19:44.310-0600		file dump/ycsb/usertable.bson is 4526386054 bytes
restore error: error writing bulk insert: E11000 duplicate key error dup key: { : "user100000112053033450" }