How can I move a database from one server to another?

Question

How can I move MySQL tables from one physical server to another?

Such as this exact scenario: I have a MySQL server that uses innodb table and is about 20GB size.

I want to move it to a new server, what's the most efficient way to do this?

Answer 1

My favorite way is to pipe a sqldump command to a sql command. You can do all databases or a specific one. So, for instance,

mysqldump -uuser -ppassword myDatabase | mysql -hremoteserver -uremoteuser -premoteserver 

You can do all databases with

mysqldump --all-databases -uuser -ppassword | mysql -hremoteserver -uremoteuser -premoteserver 

The only problem is when the database is too big and the pipe collapses. In that case, you can do table by table or any of the other methods mentioned above.

Answer 2

You don't even need mysqldump if you're moving a whole database schema, and you're willing to stop the first database (so it's consistent when being transfered)

1. Stop the database (or lock it)
2. Go to the directory where the mysql data files are.
3. Transfer over the folder (and its contents) over to the new server's mysql data directory
4. Start back up the database
5. On the new server, issue a 'create database' command.'
6. Re-create the users & grant permissions.

I can't remember if mysqldump handles users and permissions, or just the data ... but even if it does, this is way faster than doing a dump & running it. I'd only use that if I needed to dump a mysql database to then re-insert into some other RDBMS, if I needed to change storage options (innodb vs. myisam), or maybe if I was changing major versins of mysql (but I think I've done this between 4 & 5, though)

Answer 3

1. If you have ssh access you can use mysqldump from the command line
2. If you don't have ssh access but you have phpMyAdmin access you can use it to export/import
3. If you don't have phpMyAdmin access there are some handy php scripts that will dump and import ( however speaking from my own experience i never found one that is as reliable as phpMyAdmin ).

There might be this posibility where you move the actual database files ( for my install they are located at /var/lib/mysql ) , but i'm not realy shure how it will act/work out .

Answer 4

I recently moved a 30GB database with the following stragegy:

Old Server

• Stop mysql server
• Copy contents of datadir to another location on disk (~/mysqldata/*)
• Start mysql server again (downtime was 10-15 minutes)
• compress the data (tar -czvf mysqldata.tar.gz ~/mysqldata)
• copy the compressed file to new server

New Server

• install mysql (don't start)
• unzip compressed file (tar -xzvf mysqldata.tar.gz)
• move contents of mysqldata to the datadir
• Make sure your innodb_log_file_size is same on new server, or if it's not, don't copy the old log files (mysql will generate these)
• Start mysql

Answer 5

According to the MySQL 5.0 Certification Study Guide, Chapter 32 Section 32.3.4, Pages 456,457 describe the Conditions for Binary Potability which bring out the following:

Binary portability is important if you want to take a binary backup that was made on one machine and use it on another machine that has a different architecture. For example, using a binary backup is one way to copy databases from one MySQL server to another.

For MyISAM, binary portability means that you can directly copy the files for a MyISAM table from one MySQL server to another on a different machine and the second server will be able to access the table.

For InnoDB, binary portability means that you can directly copy the tablespace files from a MySQL server on one machine to another server on a different machine and the second server will be able to access the tablespace. By default, all the InnoDB tables managed by a server are stored together in the tablespace, so portability of the tablespace is a function of whether all individual InnoDB tables are portable. If even one table is not portable, neither is the tablespace.

MyISAM tables and InnoDB tablespaces are binary portable from one host to another if two conditions are met:

• Both machines must use two's-complement integer arithmetic
• Both machines must use IEEE floating-point format or else the tables must contain no floating-point columns (FLOAT or DOUBLE)

In practice, those two conditions pose little restriction. Two's-complement integer arithmetic and IEEE floating-point format are the norm on modern hardware. A third condition for InnoDB binary portability is that you should use lowercase names for tables and databases. This is because InnoDB stores these names internally (in its data dictionary) in lowercase on Windows. Using lowercase names allows binary portability between Windows and Unix, to force the use of lowercase names, you can put the following lines in an option file:

[mysqld]
lower_case_table_names=1

If you configure InnoDB to use per-table tablespaces, the conditions for binary portability are extended to include the .ibd files for InnoDB tables as well. (The conditions for the shared tablespaces still appliy because it contains the data dictionary that stores information about all InnoDB tables.)

If conditions for binary portability are not satisfied, you can copy MyISAM or InnoDB tables from one server to another by dumping them using some text format (for example, with mysqldump) and reloading them into the destination server.

There are two major ways based on storage engine to move individual tables.

For the given example we will suppose the following:

1. datadir is /var/lib/mysql
2. database called mydb
3. table in mydb database called mytable.

MyISAM tables

If mydb.mytable uses the MyISAM storage engine, the table will physically be manifested as three separate files

1. /var/lib/mysql/mydb/mytable.frm (.frm file)
2. /var/lib/mysql/mydb/mytable.MYD (.MYD file)
3. /var/lib/mysql/mydb/mytable.MYI (.MYI file)

The .frm contains the table structure
The .MYD contains the table data
The .MYI contains the table index page

These files are used interdependently to represent the table from a logical standpoint in mysql. Since these file have no further logical association attach to it, migrating a table from one DB server to another. You can even to this from a Windows server to a Linux Server or a MacOS. Of course, you could shutdown mysql and copy the 3 table files. You could run the following:

LOCK TABLES mydb.mytable READ;
SELECT SLEEP(86400);
UNLOCK TABLES;

in one ssh session to hold table as read only and hold the lock for 24 hours. One second later, perform the copy in another ssh session. Then kill the mysql session with the 24 hour lock. You need not wait 24 hours.

InnoDB tables

Based on the aforementioned quote from the Certification book, there are many factors that govern how to backup a specific InnoDB table. For sake of simplicity, clarity, and brevity, simply perform a mysqldump of the desired table using the --single-transaction parameters to have perfect point-in-time dump of the table. No need to cncern yourself with InnoDB semantics if you just want one table. You can reload that dumpfile to any MySQL server of your choose.

Since two questions were merged here (jcolebrand): EDIT

If you are more than willing to live with some slow DB performance, you can perform a series of rsyncs from the old server (ServerA) to the new server (ServerB) even while mysql is still running on ServerA.

Step 01) install the same version of mysql on ServerB that ServerA has

Step 02) On ServerA, run SET GLOBAL innodb_max_dirty_pages_pct = 0; from mysql and about 10 minutes (This purges dirty pages from the InnoDB Buffer Pool. It also helps perform a mysql shutdown faster) If your database is all MyISAM, you can skip this step.

Step 03) rsync /var/lib/mysql of ServerA to /var/lib/mysql on ServerB

Step 04) Repeat Step 03 until an rsync takes less than 1 minute

Step 05) service mysql stop on ServerA

Step 06) Perform one more rsync

Step 07) scp ServerA:/etc/my.cnf to ServerB:/etc/.

Step 08) service mysql start on ServerB

Step 08) service mysql start on ServerA (optional)

Give it a Try !!!

CAVEAT

You can create a replication slave like this. Just remember to have server-id explcitly set in the master /etc/my.cnf and a different number for server-id in the slave /etc/my.cnf

Answer 6

If you just want to move a specific table try:

mysqldump -u username -ppassword databasename tablename > databasename.tablename.sql

You can specify more table names above, in the same command. Once the command completes, move the databasename.tablename.sql file to the other server and then restore using:

mysql -u username -ppassword databasename < databasename.tablename.sql

Note that the back .sql file is created using the mysqldump program, and the restore is done directly into mysql.

Answer 7

You're going to need to take a downtime. It's going to take a while depending on what your network speed is. I'm going to assume your running MySQL on Linux/Unix. Here's the process I use:

1. Stop the mysql daemon on the source host.
2. Make a tmp folder on your target host to receive the files.
3. Use screen to make a shell session that will survive should your ssh get disconnected.
4. Use rsync to transfer the files between hosts. Something like: rsync -avhP source user@targethost:/path/to/folder/
5. Run your test cases to make sure you didn't lose anything in the transfer.

Then proceed as usual getting the local MySQL set up.

*Note: you can also use the -c parameter with rsync to add a checksum to the transfer, however this will be sloooow depending on CPU speed.

Answer 8

are you moving it to another mysql server db ? if so use, do an export on it

# mysqldump -u username -ppassword database_name > FILE.sql

Answer 9

Generic linux method:

/etc/init.d/mysqld stop
rsync -avz source_files destination
vi /etc/my.cnf

edit the datadir (and socket) for both mysqld and mysqld_safe (if applicable) to point to the new location, then

/etc/init.d/mysql start

I posted this because no one seemed simply list out the least amount of steps to do this and I feel it's the simplest way personally.