Change # of Databases in Multi-DB Plugin


I installed and configured the Multi-DB plugin for 16 databases a while ago. How can I change it to 256 databases? Is it even possible?


  • Jude

    Howdy Scott

    Hope you're doing great !!

    Im just rephrasing what the developer said

    Unfortunately there isn't a "step up" procedure. You need to do the following.

    1. Export all databases to SQL files.
    2. Create a new blank database.
    3. Import all exported databases into the new one, effectively recreating a one database system.
    4. Set up your wp install to use this single db to check it's ok.
    5. Drop all your current multi-db databases as they are incorrectly named for a 4096 setup.

    Then start from scratch with your multi-db setup, but for 4096 databases this time. So:
    1. Create 4096 databases
    2. Create the user and assign to all the db's
    3. Run move-blogs
    4. Setup db-config to use 4096 databases.

    Which is why I always say, when the question arises, that you should set up the number of databases that you think you "may" need from the outset.


  • Scott

    Hi Jude or Anyone at Support,

    Which databases do I export and import? I have a 16 database setup now and want to change it to a 256 setup. I have the main original database, then the other 15 databases, then the global database.

    My databases end in 1-9 and a-f and the Global one, plus the main original one.
    Do I export the main original database and all the others then import them all into the new database?
    The main original database is too big to import. I tried and it errors out.
    Do I just export/import all the other databases then?
    I tried that and changed the database name in wp-config and now I get a database connection error.

    Can you be a little more specific and detailed in the Steps 1-4?


  • Scott

    Okay, so let me make sure I got this right...

    I need to export ALL the databases, even the main primary database that was the original one before I installed MultiDB? If yes, then that is the one I didn't do because it was too big and error'd out on me when trying to import it. Your above link will help in me getting it exported properly.

    I see in my list of databases, the original main DB, and then the other 16 DBs (ending 1-9 and a-f), plus the 1 Global one. So that is 17 different DBs.

    So to do this... I need to export all those 17 DBs and import them all back into a newly created DB, right?

    Then all I have to do next is update the wp-config file with my new database name and check to make sure the website still works. Then if yes, delete the other DBs?

    Is that right so far?

    Then, all I would need to after that is follow the setup process from the beginning again but this time do it for the 256DBs?

    I think I got it, but want to make totally sure, because today I tried it and got that 'no connection to DB' error. I was able to restore my site luckily and now want to try it again.

    I think the problem was that I didn't export the original main DB. =(

    Let me know if I am right, so I can dive back into this.


  • Michelle Shull

    Hi Scott!

    I appreciate and understand your hesitation here, DB is nothing to take lightly. So good on you for being cautious.

    1. Take a backup first.
    2. Yep, you're going to export all the databases, including the primary, and rebuild a brand new DB with all the tables from your seventeen current DBs.
    3. From there, you're going to start the MultiDB process from scratch, so you want a completely fresh canvas to start with.

    We're here if you need us!

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