注册后的用户都在哪个地方存放呢？
db.createUser(
... {
... user: "admin",
... pwd: "admin",
... roles: [ { role: "userAdminAnyDatabase", db: "admin" } ]
... }
... )
Successfully added user: {
"user" : "admin",
"roles" : [
{
"role" : "userAdminAnyDatabase",
"db" : "admin"
}
]
}

show collections
admin
system.users
system.version

db.admin.find().count();
0