Changing MongoDB data store directory

Question

Until now I have not been specifying a MongoDB data directory and have had only one 30 GB primary partition   I just ran out of space and added a new hard disk  How can I transfer my data  that is apparently in  var lib mongodb   and configure MongoDB so that everything runs off of the new disk without affecting my existing installation

User · Answer

In debian ubuntu  you ll need to edit the  etc init d mongodb script  Really  this file should be pulling the settings from  etc mongodb conf but it doesn t seem to pull the default directory  probably a bug   This is a bit of a hack  but adding these to the script made it start correctly   add   DBDIR  database mongodb   change   DAEMON OPTS   DAEMON OPTS - --unixSocketPrefix  RUNDIR --config  CONF run     to   DAEMON OPTS   DAEMON OPTS - --unixSocketPrefix  RUNDIR --dbpath  DBDIR --config  CONF run

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Create a file called mongod cfg in MongoDB folder if you dont have it  In my case  C  Users ivanbtrujillo MongoDB  Then  edit mongod cfg with notepad and add a line with the following  our custom dbpath    dbpath C  Users ivanbtrujillo MongoDB data db   In this file you should especify the logpath too  My mongod cfg file is   logpath C  Users ivanbtrujillo MongoDB log mongo log dbpath C  Users ivanbtrujillo MongoDB data db   If you uses mongoDB as a windows service  you have to change this key and especify the mongod cfg file   To install mongodb as a windows service run this command      C  Users ivanbtrujillo MongoDB bin mongod exe  --config  C  Users ivanbtrujillo MongoDB mongod cfg     install     Open regedit exe and go to the following route   HKEYLOCALMACHINE SYSTEM CurrentControlSet services MongoDB   MongoDB service does not work  we have to edit the ImagePath key  delete its content and put the following      C  Users ivanbtrujillo MongoDB bin mongod exe  --config  C  Users ivanbtrujillo MongoDB mongod cfg   --logpath  C  Users ivanbtrujillo MongoDB log mongo log     service     We indicates to mongo it s config file and its logpath   Then when you init the mongodb service  it works   Here is a full tutorial to install mongoDB in windows  http   ivanbtrujillo herokuapp com 2014 07 24 installing-mongodb-as-a-service-windows   Hope it helps

User · Answer

If installed via apt-get in Ubuntu 12 04  don t forget to chown -R mongodb nogroup  path to new directory  Also  change the configuration at  etc mongodb conf   As a reminder  the mongodb-10gen package is now started via upstart  so the config script is in  etc init mongodb conf  I just went through this  hope googlers find it useful

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The following command will work for you  if you want to change default path  Just type this in bin directory of mongodb   mongod --dbpath yourdirectory data db   In case you want to move existing data too  then just copy all the folders from existing data db directory to new directory before you execute the command   And also stop existing mongodb services which are running

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Resolved it in 2 minutes downtime    Just move your folder  add symlink  then tune permissions  sudo service mongod stop sudo mv mongodb  new disk mongodb  sudo ln -s  new disk mongodb   var lib mongodb sudo chown mongodb mongodb  new disk mongodb  sudo service mongod start    test if mongodb user can access new location  sudo -u mongodb -s cd  new disk mongodb    resolve other permissions issues if necessary sudo usermod -a -G  lt newdisk grp gt  mongodb

User · Answer

Here is what I did  hope it is helpful to anyone else    Steps    Stop your services that are using mongodb Stop mongod - my way of doing this was with my rc file  etc rc d rc mongod stop  if you use something else  like systemd you should check your documentation how to do that Create a new directory on the fresh harddisk - mkdir  mnt database Make sure that mongodb has privileges to read   write from that directory   usually chown mongodb mongodb -R  mnt database mongodb   - thanks  DanailGabenski  Copy the data folder of your mongodb to the new location - cp -R  var lib mongodb   mnt database  Remove the old database folder - rm -rf  var lib mongodb  Create symbolic link to the new database folder - ln -s  mnt database mongodb  var lib mongodb Start mongod -  etc rc d rc mongod start Check the log of your mongod and do some sanity checking   try mongo to connect to your database to see if everything is all right   Start your services that you stopped in point 1   There is no need to tell that you should be careful when you do this  especialy with rm -rf but I think this is the best way to do it   You should never try to copy database dir while mongod is running  because there might be services that write   read from it which will change the content of your database

User · Answer

I found a special case that causes symlinks to appear to fail  I did a standard enterprise install of mongodb but changed the  var lib mongodb to a symlink as I wanted to use an XFS filesystem for my database folder and a third filesystem for the log folder   sudo systemctl start mongod    fails with a message no permission to write to mongodb log    but it succceded if I started with the same configuration file     as the owner of the external drives  ziggy  I was able to start  mongod --config  etc mongodb conf --fork I eventually discovered that    the symlinks pointed to a different filesystem and the mongodb  user  did not have permission to browse the folder that the symlink referred  Both the symlinks and the folders the symlinks referred had expansive rights to the mongod user so it made no sense   var log mongodb was changed  from the std ent install  to a symlink AND I had checked before    ll  var log mongodb lrwxrwxrwx 1 mongodb mongodb 38 Oct 28 21 58  var log mongodb - gt   media ziggy XFS DB mongodb log    ll -d  media ziggy Ext4DataBase mongodb log drwxrwxrwx 2 mongodb mongodb 4096 Nov  1 12 05  media ashley XFS DB mongodb log     But so it seemed to make no sense   of course user mongodb had rwx access to the link  the folder and to the file mongodb log    but it couldnt find it via the symlink because the BASE folder of the media couldnt be searched by mongodb  SO   I EVENTUALLY DID THIS    ll  media ziggy      drwx------  5 ziggy ziggy  4096 Oct 28 21 49 XFS DB  and found the offending missing x permissions    chmod a x  media ziggy XFS DB solved the problem Seems stupid in hindsight but no searches turned up anything useful

User · Answer

The short answer is that the --dbpath parameter in MongoDB will allow you to control what directory MongoDB reads and writes it s data from       mongod --dbpath  usr local mongodb-data   Would start mongodb and put the files in  usr local mongodb-data   Depending on your distribution and MongoDB installation  you can also configure the mongod conf file to do this automatically     Store data in  usr local var mongodb instead of the default  data db dbpath    usr local var mongodb   The official 10gen Linux packages  Ubuntu Debian or CentOS Fedora  ship with a basic configuration file which is placed in  etc mongodb conf  and the MongoDB service reads this when it starts up   You could make your change here

User · Answer

Copy the contents of  var lib mongodb to  data db  The files you should be looking for should have names like  your db name ns and your dbname n where n is a number starting with 0  If you do not see such files under  var lib mongodb  search for them on your filesystem   Once copied over  use --dbpath  data db when starting MongoDB via the mongod command

User · Answer

For me  the user was mongod instead of mongodb  sudo chown mongod mongod  newlocation  You can see the logs for errors if the service fails    var log mongodb mongod log

[mongodb] Changing MongoDB data store directory

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