I am using mongodb with 2 shard clusters and Mongoid 3.0.0.
Each shard is a replica set of 3 machines.

I configured shards yesterday and change mongoid.yml to point a mongos server.
For shard test, I inserted 1,200,000 Phonebook models into sharded database using ruby script. (Running with rails runner command)
Script ended successfully and shard key works well so there are 500,000 models in shard 1 and 700,000 models in shard 2.

But when I'm using rails console, Phonebook.count returns only 500,000.
In mongodb console, db.phonebooks.count() returns 1,200,000.

So I checked mongos log, above two queries was different!
Phonebook.count was logged
single query: mongoid.$cmd { count: "phonebooks", query: {} } ntoreturn: -1 options : 4

db.phonebooks.count() was logged
single query: mongoid.$cmd { count: "phonebooks", query: {}, fields: {} } ntoreturn: -1 options : 0

Can I make Phonebook.count() returns # of all shards collection?

P.S
I also tested destroy_all command in rails console.
Phonebook.all.destroy_all returns 500,000 for result, but actually all phonebooks in two shards was removed. (1,200,000 models removed. )