MongoDBのCollectionを削除しても容量が減らない対応 ref: http://qiita.com/noblejasper/items/4f391309ced03ae02e7e

file0.txt

set:PRIMARY> use dbname;
set:PRIMARY> db.collectionname.drop()

file1.txt

set:PRIMARY> rs.remove("10.120.41.196:27017")

file2.txt

set:REMOVED> use admin;
set:REMOVED> db.shutdownServer();

file3.sh

$ sudo rm -r /var/lib/mongodb/*
$ sudo rm -r /var/log/mongodb/*

file4.sh

$ sudo service mongod start

file5.txt

set:PRIMARY> rs.add("10.120.41.196:27017") # 追加するSECONDARY

file6.sh

> rs.syncFrom('10.120.41.199:27017') # もう一つのSECONDARY

file6.txt

> rs.syncFrom('10.120.41.199:27017') # もう一つのSECONDARY

file7.txt

set:PRIMARY> rs.status()

file8.txt

set:PRIMARY> rs.freeze(15)
set:PRIMARY> rs.stepDown(1)