Mongodb 在mongod服务器中创建复制后会出现什么问题？

在mongodb中，我创建了一个又一个复制 然后再次在没有复制的情况下启动mongod服务器，它会发出类似
在下面为什么这些警告同时出现在mongod服务器和MongoClient中

mongod服务器：

2015-06-24T11:48:21.295+0530 I STORAGE  [initandlisten] ** WARNING: mongod start
ed without --replSet yet 1 documents are present in local.system.replset
2015-06-24T11:48:21.296+0530 I STORAGE  [initandlisten] **          Restart with
--replSet unless you are doing maintenance and  no other clients are connected.

2015-06-24T11:48:21.296+0530 I STORAGE  [initandlisten] **          The TTL coll
ection monitor will not start because of this.
2015-06-24T11:48:21.296+0530 I STORAGE  [initandlisten] **
2015-06-24T11:48:21.297+0530 I STORAGE  [initandlisten]  For more info see http:
//dochub.mongodb.org/core/ttlcollections
2015-06-24T11:48:21.298+0530 I STORAGE  [initandlisten]
2015-06-24T11:48:21.299+0530 I NETWORK  [initandlisten] waiting for connections
on port 27017
2015-06-24T11:48:39.269+0530 I NETWORK  [initandlisten] connection accepted from
127.0.0.1:2979 #1 (1 connection now open)

mongo客户端：

2015-06-24T11:48:39.233+0530 I CONTROL  Hotfix KB2731284 or later update is not
installed, will zero-out data files
MongoDB shell version: 3.0.2
connecting to: test
Server has startup warnings:
2015-06-24T11:48:21.295+0530 I STORAGE  [initandlisten]
2015-06-24T11:48:21.295+0530 I STORAGE  [initandlisten] ** WARNING: mongod start
ed without --replSet yet 1 documents are present in local.system.replset
2015-06-24T11:48:21.296+0530 I STORAGE  [initandlisten] **          Restart with
--replSet unless you are doing maintenance and  no other clients are connected.

2015-06-24T11:48:21.296+0530 I STORAGE  [initandlisten] **          The TTL coll
ection monitor will not start because of this.
2015-06-24T11:48:21.298+0530 I STORAGE  [initandlisten]