How to do it...

1. Start mongod daemon with no special parameters:

/data/mongodb/bin/mongod --dbpath /data/db

1. Connect to mongo shell, create a test db and insert a sample document:

mongo localhost:27017
> use mydb
> db.mycol.insert({foo:1})

1. Inspect the /data/db directory structure, it should look something like this:

ls /data/db
total 244
drwxr-xr-x  4 root root  4096 May 21 08:45 .
drwxr-xr-x 10 root root  4096 May 21 08:42 ..
-rw-r--r--  1 root root 16384 May 21 08:43 collection-0-626293768203557661.wt
-rw-r--r--  1 root root 16384 May 21 08:43 collection-2-626293768203557661.wt
-rw-r--r--  1 root root 16384 May 21 08:43 collection-5-626293768203557661.wt
drwxr-xr-x  2 root root  4096 May 21 08:45 diagnostic.data
-rw-r--r--  1 root root 16384 May 21 08:43 index-1-626293768203557661.wt
-rw-r--r--  1 root root 16384 May 21 08:43 index-3-626293768203557661.wt
-rw-r--r--  1 root root 16384 May 21 08:43 index-4-626293768203557661.wt
-rw-r--r--  1 root root 16384 May 21 08:43 index-6-626293768203557661.wt
drwxr-xr-x  2 root root  4096 May 21 08:42 journal
-rw-r--r--  1 root root 16384 May 21 08:43 _mdb_catalog.wt
-rw-r--r--  1 root root     6 May 21 08:42 mongod.lock
-rw-r--r--  1 root root 16384 May 21 08:44 sizeStorer.wt
-rw-r--r--  1 root root    95 May 21 08:42 storage.bson
-rw-r--r--  1 root root    49 May 21 08:42 WiredTiger
-rw-r--r--  1 root root  4096 May 21 08:42 WiredTigerLAS.wt
-rw-r--r--  1 root root    21 May 21 08:42 WiredTiger.lock
-rw-r--r--  1 root root   994 May 21 08:45 WiredTiger.turtle
-rw-r--r--  1 root root 61440 May 21 08:45 WiredTiger.wt

1. Shutdown the previous mongod instance.

 

1. Create a new db path and start mongod with --directoryperdb option:

mkdir /data/newdb
/data/mongodb/bin/mongod --dbpath /data/newdb --directoryperdb

1. Connect to the mongo shell, create a test db, and insert a sample document:

mongo localhost:27017
> use mydb
> db.mycol.insert({bar:1})

1. Inspect the /data/newdb directory structure, it should look something like this:

ls /data/newdb
total 108
drwxr-xr-x  7 root root  4096 May 21 08:42 .
drwxr-xr-x 10 root root  4096 May 21 08:42 ..
drwxr-xr-x  2 root root  4096 May 21 08:41 admin
drwxr-xr-x  2 root root  4096 May 21 08:42 diagnostic.data
drwxr-xr-x  2 root root  4096 May 21 08:41 journal
drwxr-xr-x  2 root root  4096 May 21 08:41 local
-rw-r--r--  1 root root 16384 May 21 08:42 _mdb_catalog.wt
-rw-r--r--  1 root root     0 May 21 08:42 mongod.lock
drwxr-xr-x  2 root root  4096 May 21 08:41 mydb
-rw-r--r--  1 root root 16384 May 21 08:42 sizeStorer.wt
-rw-r--r--  1 root root    95 May 21 08:41 storage.bson
-rw-r--r--  1 root root    49 May 21 08:41 WiredTiger
-rw-r--r--  1 root root  4096 May 21 08:42 WiredTigerLAS.wt
-rw-r--r--  1 root root    21 May 21 08:41 WiredTiger.lock
-rw-r--r--  1 root root   986 May 21 08:42 WiredTiger.turtle
-rw-r--r--  1 root root 28672 May 21 08:42 WiredTiger.wt