MongoDB, change db path, not working - mongodb

Question

I upgraded from debian 6 to debian 8. After that I upgraded MongoDB from ~2.5 to 3.2.9. They seemed to have changed the db path since I could not see any of my databases. I upgraded the dbpath. Stil I can't see any of my databases.
seprst#SESTOWS011:/data/db$ ls
graddays graddays.0 graddays.ns journal local local.0 local.ns mongod.lock mypdb mypdb.0 mypdb.ns
seprst#SESTOWS011:/data/db$ sudo service mongod stop
seprst#SESTOWS011:/data/db$ mongod --dbpath /data/db
2016-08-17T12:02:26.468+0200 I CONTROL [initandlisten] MongoDB starting : pid=22283 port=27017 dbpath=/data/db 64-bit host=SESTOWS011
2016-08-17T12:02:26.468+0200 I CONTROL [initandlisten] db version v3.2.9
2016-08-17T12:02:26.468+0200 I CONTROL [initandlisten] git version: 22ec9e93b40c85fc7cae7d56e7d6a02fd811088c
2016-08-17T12:02:26.468+0200 I CONTROL [initandlisten] OpenSSL version: OpenSSL 1.0.1t 3 May 2016
2016-08-17T12:02:26.469+0200 I CONTROL [initandlisten] allocator: tcmalloc
2016-08-17T12:02:26.469+0200 I CONTROL [initandlisten] modules: none
2016-08-17T12:02:26.469+0200 I CONTROL [initandlisten] build environment:
2016-08-17T12:02:26.469+0200 I CONTROL [initandlisten] distmod: debian71
2016-08-17T12:02:26.469+0200 I CONTROL [initandlisten] distarch: x86_64
2016-08-17T12:02:26.469+0200 I CONTROL [initandlisten] target_arch: x86_64
2016-08-17T12:02:26.469+0200 I CONTROL [initandlisten] options: { storage: { dbPath: "/data/db" } }
2016-08-17T12:02:26.513+0200 I - [initandlisten] Detected data files in /data/db created by the 'mmapv1' storage engine, so setting the ac tive storage engine to 'mmapv1'.
2016-08-17T12:02:26.530+0200 I JOURNAL [initandlisten] journal dir=/data/db/journal
2016-08-17T12:02:26.545+0200 I JOURNAL [initandlisten] recover : no journal files present, no recovery needed
2016-08-17T12:02:26.590+0200 I JOURNAL [initandlisten] warning couldn't write to / rename file /data/db/journal/prealloc.0: couldn't open file / data/db/journal/prealloc.0 for writing errno:9 Bad file descriptor
2016-08-17T12:02:26.590+0200 I STORAGE [initandlisten] exception in initAndListen: 13516 couldn't open file /data/db/journal/j._0 for writing er rno:9 Bad file descriptor, terminating
2016-08-17T12:02:26.590+0200 I CONTROL [initandlisten] now exiting
2016-08-17T12:02:26.590+0200 I NETWORK [initandlisten] shutdown: going to close listening sockets...
2016-08-17T12:02:26.590+0200 I NETWORK [initandlisten] removing socket file: /tmp/mongodb-27017.sock
2016-08-17T12:02:26.590+0200 I NETWORK [initandlisten] shutdown: going to flush diaglog...
2016-08-17T12:02:26.590+0200 I NETWORK [initandlisten] shutdown: going to close sockets...
2016-08-17T12:02:26.591+0200 I STORAGE [initandlisten] shutdown: waiting for fs preallocator...
2016-08-17T12:02:26.591+0200 I STORAGE [initandlisten] shutdown: final commit...
2016-08-17T12:02:26.591+0200 I STORAGE [initandlisten] shutdown: closing all files...
2016-08-17T12:02:26.591+0200 I STORAGE [initandlisten] closeAllFiles() finished
2016-08-17T12:02:26.591+0200 I CONTROL [initandlisten] dbexit: rc: 100
seprst#SESTOWS011:/data/db$ sudo service mongod start
seprst#SESTOWS011:/data/db$ mongo
MongoDB shell version: 3.2.9
connecting to: test
Server has startup warnings:
2016-08-17T12:02:40.540+0200 I CONTROL [initandlisten]
2016-08-17T12:02:40.540+0200 I CONTROL [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/defrag is 'always'.
2016-08-17T12:02:40.540+0200 I CONTROL [initandlisten] ** We suggest setting it to 'never'
2016-08-17T12:02:40.540+0200 I CONTROL [initandlisten]
> show dbs
local 0.000GB
>
Any suggestions?

Answer 1

there is formatting issue with comment so posting as answer
ps -xa | grep mongod
open config file cat /etc/mongod.conf
for me it's dbPath: /var/lib/mongodb
you can check your settings.
to make changes permanent at your own risk
sudo service mongod stop
sudo ln -s /data/db/ /var/lib/mongodb
sudo chown mongodb:mongodb /data/db/
sudo service mongod start
//test if mongodb user can access new location:
sudo -u mongodb -s cd /data/db/