So updated the doc with ip_count hash:

Field
field :ip_count, :type => Hash, :default => {}

MONGODB doc update
ca_development['account'].update(

{"_id"=>BSON::ObjectId('4d8ed14ebae81c589a000022')}

, {"$set"=>{"ip_count"=>{"201103"=>{"127.0.0.1"=>1}}}})

But when the doc is reloaded the data is gone!!

ip_count: nil