$ mongo localhost:31200
MongoDB shell version: 2.5.0-pre-
connecting to: localhost:31200/test
Server has startup warnings:
Wed Apr 10 18:43:07.479 [initandlisten]
Wed Apr 10 18:43:07.479 [initandlisten] ** NOTE: This is a development version (2.5.0-pre-) of MongoDB.
Wed Apr 10 18:43:07.479 [initandlisten] **       Not recommended for production.
Wed Apr 10 18:43:07.479 [initandlisten]
anden(mongod-2.5.0-pre-)[PRIMARY/SHARDING-rs1] test> rs.config()
{
  "_id": "SHARDING-rs1",
  "version": 4,
  "members": [
    {
      "_id": 0,
      "host": "anden.local:31200",
      "tags": {
        "dc": "ny",
        "server": "0"
      }
    },
    {
      "_id": 1,
      "host": "anden.local:31201",
      "tags": {
        "dc": "hobo",
        "server": "1",
        "theOtherShard": "doesntHaveThisTag"
      }
    },
    {
      "_id": 2,
      "host": "anden.local:31202",
      "priority": 0,
      "tags": {
        "dc": "sf",
        "server": "2"
      }
    }
  ],
  "settings": {
    "getLastErrorModes": {
      "ALL": {
        "server": 3
      },
      "AllDC": {
        "dc": 2
      },
      "AnyDC": {
        "dc": 1
      },
      "Broken": {
        "theOtherShard": 1
      }
    }
  }
}
anden(mongod-2.5.0-pre-)[PRIMARY/SHARDING-rs1] test> db.test.insert({foo: "bar"})
Inserted 1 record(s) in 1ms
anden(mongod-2.5.0-pre-)[PRIMARY/SHARDING-rs1] test> db.runCommand({getLastError:1,w:"AllDC",wtimeout: 1000});
{
  "n": 0,
  "lastOp": Timestamp(1365655128, 1),
  "connectionId": 417,
  "wtimeout": true,
  "waited": 1000,
  "writtenTo": [
    {
      "_id": 0,
      "host": "anden.local:31200",
      "tags": {
        "dc": "ny",
        "server": "0"
      }
    },
    {
      "_id": 1,
      "host": "anden.local:31201",
      "tags": {
        "dc": "hobo",
        "server": "1",
        "theOtherShard": "doesntHaveThisTag"
      }
    },
    {
      "_id": 2,
      "host": "anden.local:31202",
      "priority": 0,
      "tags": {
        "dc": "sf",
        "server": "2"
      }
    }
  ],
  "err": "timeout",
  "ok": 1
}
anden(mongod-2.5.0-pre-)[PRIMARY/SHARDING-rs1] test>