MongoDB --dbpath giving access to old data - mongodb

Question

I have mongo installed on my local machine. When I start the database by running mongod I got this error (that is fairly common, and this site has solutions to workarounds):
$ mongod
mongod --help for help and startup options
2015-01-01T22:31:17.350-0600 [initandlisten] MongoDB starting : pid=2835 port=27017 dbpath=/data/db 64-bit host=hermes
2015-01-01T22:31:17.351-0600 [initandlisten] db version v2.6.4
2015-01-01T22:31:17.351-0600 [initandlisten] git version: nogitversion
2015-01-01T22:31:17.351-0600 [initandlisten] build info: Darwin minimavericks.local 13.3.0 Darwin Kernel Version 13.3.0: Tue Jun 3 21:27:35 PDT 2014; root:xnu-2422.110.17~1/RELEASE_X86_64 x86_64 BOOST_LIB_VERSION=1_49
2015-01-01T22:31:17.351-0600 [initandlisten] allocator: tcmalloc
2015-01-01T22:31:17.351-0600 [initandlisten] options: {}
2015-01-01T22:31:17.351-0600 [initandlisten] exception in initAndListen: 10296
*********************************************************************
ERROR: dbpath (/data/db) does not exist.
Create this directory or give existing directory in --dbpath.
See http://dochub.mongodb.org/core/startingandstoppingmongo
*********************************************************************
, terminating
2015-01-01T22:31:17.351-0600 [initandlisten] dbexit:
2015-01-01T22:31:17.351-0600 [initandlisten] shutdown: going to close listening sockets...
2015-01-01T22:31:17.351-0600 [initandlisten] shutdown: going to flush diaglog...
2015-01-01T22:31:17.351-0600 [initandlisten] shutdown: going to close sockets...
2015-01-01T22:31:17.351-0600 [initandlisten] shutdown: waiting for fs preallocator...
2015-01-01T22:31:17.351-0600 [initandlisten] shutdown: lock for final commit...
2015-01-01T22:31:17.351-0600 [initandlisten] shutdown: final commit...
2015-01-01T22:31:17.351-0600 [initandlisten] shutdown: closing all files...
2015-01-01T22:31:17.352-0600 [initandlisten] closeAllFiles() finished
2015-01-01T22:31:17.355-0600 [initandlisten] dbexit: really exiting now
I created a directory in my development environment at /my/curent/directory/data/db and started mongo again with $ mongod --dbpath /my/curent/directory/data/db, this time producing:
2015-01-01T22:32:31.282-0600 [initandlisten] options: { storage: { dbPath: "./data/db" } }
2015-01-01T22:32:31.319-0600 [initandlisten] journal dir=./data/db/journal
2015-01-01T22:32:31.320-0600 [initandlisten] recover : no journal files present, no recovery needed
2015-01-01T22:32:31.383-0600 [FileAllocator] allocating new datafile ./data/db/local.ns, filling with zeroes...
2015-01-01T22:32:31.383-0600 [FileAllocator] creating directory ./data/db/_tmp
2015-01-01T22:32:31.482-0600 [FileAllocator] done allocating datafile ./data/db/local.ns, size: 16MB, took 0.098 secs
2015-01-01T22:32:31.842-0600 [FileAllocator] allocating new datafile ./data/db/local.0, filling with zeroes...
2015-01-01T22:32:32.756-0600 [FileAllocator] done allocating datafile ./data/db/local.0, size: 64MB, took 0.914 secs
2015-01-01T22:32:33.215-0600 [initandlisten] build index on: local.startup_log properties: { v: 1, key: { _id: 1 }, name: "_id_", ns: "local.startup_log" }
2015-01-01T22:32:33.216-0600 [initandlisten] added index to empty collection
2015-01-01T22:32:33.216-0600 [initandlisten] command local.$cmd command: create { create: "startup_log", size: 10485760, capped: true } ntoreturn:1 keyUpdates:0 numYields:0 reslen:37 1852ms
2015-01-01T22:32:33.216-0600 [initandlisten] waiting for connections on port 27017
2015-01-01T22:33:31.402-0600 [clientcursormon] mem (MB) res:33 virt:2635
2015-01-01T22:33:31.402-0600 [clientcursormon] mapped (incl journal view):160
2015-01-01T22:33:31.402-0600 [clientcursormon] connections:0
It's great. Using the mongo shell, I can access my collections that I was working with in this directory, but I can also see all of my other databases from weeks prior (when this directory did not exist) using show dbs. What purpose does the --dbpath option serve if not to isolate where data is stored? Is something weird happening here?

Answer 1

MongoDB requires a data directory to store all data. MongoDB’s default data directory path is \data\db.
To use an alternate dbpath, specify the path in the configuration file (e.g. C:\Program Files\MongoDB\mongod.cfg) or on the command line with the --dbpath option.
Read more about MongoDB Installation
If you are using windows then create data\db folder under C drive.
If you are using your own directory for data then pass full path of the folder as --dbpath argument value.

Answer 2

If MongoDB’s default data directory path "\data\db" is correct but accessing old data means just check your Task Manager.
End all mongo command and restart your mongodb. I tried it, working well