mk-slave-move.1p - Man Page

Move a MySQL slave around in the replication hierarchy.


Usage: mk-slave-move [OPTION...] SLAVE_DSN [DSN...]

mk-slave-move moves replication slave(s) around in the hierarchy.


  mk-slave-move slave --sibling-of-master

  mk-slave-move slave --slave-of-sibling sibling

  mk-slave-move slave --slave-of-uncle uncle


The following section is included to inform users about the potential risks, whether known or unknown, of using this tool.  The two main categories of risks are those created by the nature of the tool (e.g. read-only tools vs. read-write tools) and those created by bugs.

mk-slave-move is a read-write tool by default.  It manipulates replication settings.  Some of the features are incomplete, including some safety checks such as not moving slaves that have temporary tables open.

At the time of this release, we know of no bugs that could cause serious harm to users.

The authoritative source for updated information is always the online issue tracking system.  Issues that affect this tool will be marked as such.  You can see a list of such issues at the following URL: <>.

See also "Bugs" for more information on filing bugs and getting help.


This tool knows how to disconnect and reconnect slaves to each other, compare replication positions, and so on.  This makes it able to move a slave around the replication hierarchy safely and correctly.  It doesn't do anything you can't do by hand, but it is tedious and error-prone to do this by hand.

The hosts are given by a DSN.  A DSN is a special syntax that can be either just a hostname (like or, or a key=value,key=value string.  Keys are a single letter:

   === =======
   h   Connect to host
   P   Port number to use for connection
   S   Socket file to use for connection
   u   User for login if not current user
   p   Password to use when connecting
   F   Only read default options from the given file

If you omit any values in the sibling or uncle host, they are filled in with defaults from the slave host, so you don't need to specify them in both places. mk-slave-move reads all normal MySQL option files, such as ~/.my.cnf, so you may not need to specify username, password and other common options at all.

Exit Status

An exit status of 0 (sometimes also called a return value or return code) indicates success.  Any other value represents the exit status of the Perl process itself.


Specify one and only one of "--sibling-of-master", "--slave-of-sibling", "--slave-of-uncle", or "--detach".

This tool accepts additional command-line arguments.  Refer to the "Synopsis" and usage information for details.


Prompt for a password when connecting to MySQL.


short form: -A; type: string

Default character set.  If the value is utf8, sets Perl's binmode on STDOUT to utf8, passes the mysql_enable_utf8 option to DBD::mysql, and runs SET NAMES UTF8 after connecting to MySQL.  Any other value sets binmode on STDOUT without the utf8 layer, and runs SET NAMES after connecting to MySQL.


type: Array

Read this comma-separated list of config files; if specified, this must be the first option on the command line.


short form: -F; type: string

Only read mysql options from the given file.  You must give an absolute pathname.


Make this server forget that it is a slave.


Show help and exit.


short form: -h; type: string

Connect to host.


short form: -p; type: string

Password to use when connecting.


type: string

Create the given PID file.  The file contains the process ID of the script. The PID file is removed when the script exits.  Before starting, the script checks if the PID file already exists.  If it does not, then the script creates and writes its own PID to it.  If it does, then the script checks the following: if the file contains a PID and a process is running with that PID, then the script dies; or, if there is no process running with that PID, then the script overwrites the file with its own PID and starts; else, if the file contains no PID, then the script dies.


short form: -P; type: int

Port number to use for connection.


type: string; default: wait_timeout=10000

Set these MySQL variables.  Immediately after connecting to MySQL, this string will be appended to SET and executed.


Make the server a slave of its grandparent, so it is a sibling of its master.

The procedure is as follows:

 1. Connect to the server's master.
 2. Stop the slave processes on the master.
 3. Wait for the server to catch up to its master in replication.
 4. Point the slave to the master's master.

Make the server a slave of one of its siblings.  Specify the sibling as a DSN.

The procedure is as follows:

 1. Connect to the sibling and verify that it has the same master.
 2. Stop the slave processes on the server and its sibling.
 3. If one of the servers is behind the other, make it catch up.
 4. Point the slave to its sibling.

Make the server a slave of one of its uncles (parent's siblings).  Specify the uncle as a DSN.

An "uncle" is a sibling of the server's master.  The procedure is as follows:

 1. Connect to the slave's master and its uncle, and verify that both have the
    same master.  (Their common master is the slave's grandparent).
 2. Stop the slave processes on the master and uncle.
 3. If one of them is behind the other, make it catch up.
 4. Point the slave to its uncle.

short form: -S; type: string

Socket file to use for connection.


type: time; default: 10m

Timeout when waiting for replication to catch up.


short form: -u; type: string

User for login if not current user.


Show version and exit.

DSN Options

These DSN options are used to create a DSN.  Each option is given like option=value.  The options are case-sensitive, so P and p are not the same option.  There cannot be whitespace before or after the = and if the value contains whitespace it must be quoted.  DSN options are comma-separated.  See the maatkit manpage for full details.


You can download Maatkit from Google Code at <>, or you can get any of the tools easily with a command like the following:


Where toolname can be replaced with the name (or fragment of a name) of any of the Maatkit tools.  Once downloaded, they're ready to run; no installation is needed.  The first URL gets the latest released version of the tool, and the second gets the latest trunk code from Subversion.


The environment variable MKDEBUG enables verbose debugging output in all of the Maatkit tools:

   MKDEBUG=1 mk-....

System Requirements

You need Perl, DBI, DBD::mysql, and some core packages that ought to be installed in any reasonably new version of Perl.


For a list of known bugs see <>.

Please use Google Code Issues and Groups to report bugs or request support: <>.  You can also join #maatkit on Freenode to discuss Maatkit.

Please include the complete command-line used to reproduce the problem you are seeing, the version of all MySQL servers involved, the complete output of the tool when run with "--version", and if possible, debugging output produced by running with the MKDEBUG=1 environment variable.

Copyright, License and Warranty

This program is copyright 2007-2011 Baron Schwartz. Feedback and improvements are welcome.


This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2; OR the Perl Artistic License.  On UNIX and similar systems, you can issue `man perlgpl' or `man perlartistic' to read these licenses.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA.

See Also

See also mk-table-checksum, mk-table-sync, mk-slave-delay.


Baron Schwartz

About Maatkit

This tool is part of Maatkit, a toolkit for power users of MySQL.  Maatkit was created by Baron Schwartz; Baron and Daniel Nichter are the primary code contributors.  Both are employed by Percona.  Financial support for Maatkit development is primarily provided by Percona and its clients.


This manual page documents Ver 0.9.12 Distrib 7540 $Revision: 7531 $.


2024-01-25 perl v5.38.2 User Contributed Perl Documentation