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Accepted
Agvorth
Asked: 2009-07-07 13:54:40 +0800 CST

How can I copy MySQL users table from one server to another? [duplicate]

  • 772

I'm setting up up a new MySQL server and I'd like to give it the same set of usernames, allowed hosts, and passwords as an existing server (which is going away).

Would it work to just do a dump of the users table and then load it on the new server?

Is there a better way than that?

mysql user-permissions user-accounts export

5 Answers

  1. Best Answer
    oldserver$ mysqldump mysql > mysql.sql
newserver$ mysql mysql < mysql.sql
newserver$ mysql 'flush privileges;'

    Should do it, remember to add -u $USER and -p$PASSWORD as required

    • 33

  2. I would take a look at the Percona Toolkit. The description of the pt-show-grants tool says it all...

    pt-show-grants extracts, orders, and then prints grants for MySQL user accounts.

    Why would you want this? There are several reasons.

    The first is to easily replicate users from one server to another; you can simply extract the grants from the first server and pipe the output directly into another server.

    The second use is to place your grants into version control....

    • 22

  3. Whilst a dump of the mysql database would probably work, in my experience, properly documenting all the access and setting it up again with GRANT statements is much better. There are two benefits to doing it this way:

    1. You will understand your database security and how it is implemented.
    2. You will get to remove access that is no longer required.
    • 13

  4. The accepted answer (using mysqldump to backup mysql.user table) is a very dangerous approach if you are migrating to a new server version.

    I did that in the past (migrating users from Mysql 4 to Mysql 5.1), and later I had problems trying to grant or modify privileges to my database users.

    This happens because mysql.users table structure differs between mysql server versions, as explained here:

    https://dba.stackexchange.com/a/16441/18472

    So, take care if you are upgrading your server version. Some more hints here:

    https://stackoverflow.com/a/13218162/710788

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  5. mysqldump will work, but since the mysql database uses ISAM, you can just copy the directory to the new server. You'll find this in different places, but the most common location for the mysql database will be /var/lib/mysql/mysql. Be sure to stop mysql on the new server, move the old directory out of the way, copy the directory and restart. An example using standard locations as root:

    # /etc/init.d/mysqld stop
# cd /var/lib/mysql
# mv mysql ../mysql.backup
# rsync -a root@oldserver:/var/lib/mysql/mysql .
# /etc/init.d/mysql start
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