Installing a single MySQL instance on a linux machine is a very simple operation. It may be as simple as:
apt-get install mysql-server
But you cannot use this method to install another MySQL instance. Moreover, if you try to manually install another instance, you may find that some collisions occur.
For example, when trying to install two 5.0 servers, apt-get or yum will just tell me "package is already installed".
When trying to install a new 5.1 server along with 5.0, an implicit upgrade is performed.
But even if we try forcing the installation, there are collisions:
- A dpkg or rpm will install my.cnf under /etc. Two installations will override one another. With RPM you may get a .rpmsave backup file, but that doesn't help too much.
- The daemon file: /etc/init.d/mysql(d) is overwritten.
- The default data directory is used for both installations: /var/lib/mysql
- The binaries are overwritten
- Both installations will use port 3306.
- In both installations, the same socket file (e.g. /var/run/mysql/mysql.sock) is used.
Interestingly, on Windows, multiple MySQL installations are by far easier:
- Binaries are under Program Files\\MySQL\\MySQLX.X. With two installations, you specify different directories.
- Data files are by default directly under the installations paths (MySQL 5.0) or under "Documents And Settings..." (MySQL 5.1) with no collisions.
- The my.ini files are located directly under the installation paths.
- The installer asks you for a service name, and notifies you if that name is already in use.
- The installer let's you know if port 3306 is already taken, and allows you to specify another one.
- Of course, there's no unix socket file.
I usually install MySQL on Linux using the binary tarball. When there's only one instance expected, I go with the standards: my.cnf is in /etc, mysqld is under /etc/init.d, etc. (no pun intended)
Steps for multiple installation on Linux
When more than one installation is expected, here's a safe way to ensure no collisions occur. We will assume a 5.0 and 5.1 installation (say we want to upgrade):
Install the MySQL binaries under /usr/local
Following the INSTALL document file, we make symbolic links to the full path in the names
ln -s /usr/local/your-mysql-5.0-full-installation-path /usr/local/mysql50 ln -s /usr/local/your-mysql-5.1-full-installation-path /usr/local/mysql51
Do not put my.cnf under /etc
Instead, put them directly in the installation path:
touch /usr/local/mysql50/my.cnf touch /usr/local/mysql51/my.cnf
Setup different port numbers in the my.cnf files
For example, in /usr/local/mysql50/my.cnf, use port 3350:
[mysql] port=3350 [mysqld] port=3350
Choose another port (e.g. 3351) for the 5.1 installation, then have it written as above in the 5.1 my.cnf file.
Choose distinct socket files
For example, in /usr/local/mysql50/my.cnf, add:
[mysql] port=3350 socket=/tmp/mysql50.sock [mysqld] port=3350 socket=/tmp/mysql50.sock
Choose another socket and set it up in the second my.cnf file. You may also choose to put the socket files under the data paths or installation paths.
Choose distinct data paths
Either do not specify them at all, in which case they will reside under the installation path, or, if you want to enjoy another partition, use:
[mysql] port=3350 socket=/tmp/mysql50.sock [mysqld] port=3350 socket=/tmp/mysql50.sock datadir=/my_raid_path/mysql50/
Create distinct daemons
Manually copy support_files/mysql.server to /etc/init.d under distinct names. For example:
cp /usr/local/mysql50/support_files/mysql.server /etc/init.d/mysqld50 cp /usr/local/mysql51/support_files/mysql.server /etc/init.d/mysqld51
Other settings
You may wish to set up a soft link for the client binaries, for example:
ln -s /usr/local/mysql50/bin/mysql /usr/bin/mysql50
chkconfig (RedHat and derived) can be used to start/stop daemon as service:
chkconfig --add mysqld50
Conclusion
I would prefer MySQL to come bundled in self-contained directory. The tarball is almost that, except it expects socket file to be on /tmp, and by default uses the 3306 port. I would further like to have a dpkg-reconfigure script to setup the above issues.
Till then, it's manual configuration.
I could have used these instructions a few months ago.
Oddly enough, the Debian packages for PostgreSQL are all somewhat self contained, and you can install several versions in parallel, and as long as you configure the port before firing up, you can run them all at once, if you really want. It would not be that hard to make the MySQL RPM and debs that would be more parallel-installation friendly.
Link | February 19th, 2009 at 9:38 am
Ever heard of MySQL Sandbox[1]?
[1]: https://launchpad.net/mysql-sandbox
Link | February 19th, 2009 at 12:20 pm
Hi,
Indeed, I should have mentioned sandbox.
However, sandbox works for multiple installations in advance only, and does not help out with installations which are not simultaneous. Please correct me if I'm wrong.
Regards
Link | February 19th, 2009 at 2:19 pm
Don't forget there is also mysqld_multi. (http://dev.mysql.com/doc/refman/5.0/en/mysqld-multi.html). This allows multiple servers using a single set of binaries, is permanent (can survive a restart), and is most likely exactly what you want.
Link | February 19th, 2009 at 2:51 pm
MySQL sandbox might have helped me. mysql_multi would not have, as we were installing two different version since we are moving from one version to another.
Link | February 19th, 2009 at 9:27 pm
Log Buffer #136: A Carnival of the Vanities for DBAs wrote:
[...] Noach offers his HOWTO on manually installing multiple MySQL instances on Linux. He says, “Installing a single MySQL instance on a linux machine is a very simple operation. [...]
Link | February 20th, 2009 at 7:02 pm
Lots of typos have been fixed in this post, most of which appear to have been created by WordPress trying to outsmart the coder.
Link | February 24th, 2009 at 9:28 am
How does MySQL know where my.cnf is located. It seems that the alternative version is connecting through the wrong socket and so tries to read /etc/mysql/my.cnf instead of the alternative my.cnf
Link | June 12th, 2009 at 12:15 pm
Hi Andi,
Search path is described in: http://dev.mysql.com/doc/refman/5.0/en/option-files.html
And namely it looks at the installation path per installation.
But, I must say that I've been using MySQL sandbox quite a lot lately, and, if it suits your needs - it's really great! You should give it a try.
Link | June 12th, 2009 at 12:32 pm
I have been on this site already and just tried to start the alternative server this way:
bin/mysqld_safe --user=mysqlg --datadir=/usr/local/mysqlg/data &
[1] 8472
root@xx:/usr/local/mysqlg# 090612 12:55:15 mysqld_safe Logging to '/usr/local/mysqlg/data/mesolt11.err'.
090612 12:55:15 mysqld_safe The file /usr/local/mysql/bin/mysqld
does not exist or is not executable. Please cd to the mysql installation
directory and restart this script from there as follows:
./bin/mysqld_safe&
See http://dev.mysql.com/doc/mysql/en/mysqld-safe.html for more information
So you can see that I have set up an own group and user for this version and I have put the edited my.cnf to the local mysql dir.
Thank you for the tip, I will try the sandbox when I have understood more.
Link | June 12th, 2009 at 12:59 pm
Andi,
Try another one: add --basedir=/usr/local/mysqlg/
Let me know if this worked out
Shlomi
Link | June 17th, 2009 at 7:25 am
Guys thank you for starting this thread. This has been very helpful for me to get up to speed. and getting both of the mysql instances running in parallel
Andi,
I've encountered exactly the same problem, try this - i think this will resolve your problem:
/usr/local/mysqlg/bin/mysqld_safe --defaults-file=/usr/local/mysqlg/my.cnf &
By doing so you explicitly tell mysql to use your new my.cnf.
Also, i've made a change in mysqld_safe script as well to use my own user - u might want to try it as well. In my version it's on line 21 user='mysqlg'
Link | June 18th, 2009 at 12:15 am
I have tried out MySQL sandbox and recommend it to everyone - it's very easy to handle. http://mysqlsandbox.net/
Link | June 18th, 2009 at 12:12 pm
Hi,
Thanks for the information,just found this post my technorati news feed section! I was searching for this since past 3 months and i am glad to see it here. Thanking you much
Martin
Link | August 13th, 2009 at 5:46 am
Hi Martin,
I'm glad it helped. But do try MySQL sandbox. It automates so much.
Shlomi
Link | August 13th, 2009 at 6:34 am
To not yum or to not apt-get? | code.openark.org wrote:
[...] written shortly on this before. I like yum; I love apt-get; I prefer not to use them for MySQL [...]
Link | February 24th, 2010 at 11:50 pm
I created another mysql service in my linux machine as per this document mentioned. Unfortunately I couldn't start the created service. When trying to start the service, it shows some
errorERROR! MySQL server PID file could not be found!
/etc/init.d/mysqldtest: line 276: cd: /usr/local/mysql: No such file or directory
Starting MySQL ERROR! Couldn't find MySQL server (/usr/local/mysql/bin/mysqld_safe)
Could you please anyone help me... ???
Link | September 12th, 2012 at 2:03 pm
@Hasee,
Try setting the basedir param in your /etc/init.d/mysqldtest (somewhere in the top 25 lines of the file) and point it to your installation directory.
Link | September 12th, 2012 at 2:08 pm
Could you please explain it??? Iam a beginner in mysql with linux
Link | September 12th, 2012 at 2:20 pm
@Hasee,
If you are beginner, then perhaps all the above post is not for you. Nevertheless, if you followed it, then you have installed MySQL somewhere. Let's say its /usr/local/mysql55
In /etc/init.d/mysqldtest, set
basedir=/usr/local/mysql55
If you don't manage the above I strongly recommend that you do not attempt a manual dual install of MySQL.
Link | September 12th, 2012 at 7:21 pm
Iam doing the same thing in Windows successfully. But in linux, I face some difficulties. I follow your valuable suggestions, but Iam facing another problem:
Starting MySQL..................................................................................................... ERROR! The server quit without updating PID file (/var/lib/mysql/Test.pid).
Why this happends???
Link | September 13th, 2012 at 6:37 am
Windows and Linux make for two completely different installation process. You CAN'T be "doing the same thing".
I can't presume to help you out by negotiating comments. Check out your MySQL error log is the one thing I can tell you.
Otherwise, best place to get advice is stackoverflow.com, or otherwise get consulting.
Link | September 13th, 2012 at 7:18 am
Hi
I have this multiple instance on my machine with 3 different port.
How do I reset root password on every port?
Thanks
Link | October 13th, 2012 at 5:05 am
@Suryadilaga,
See this post: Recovering a MySQL `root` password: the fourth solution.
Link | October 13th, 2012 at 9:12 am
Hi shlomi,
I follow your step using mysql-init and work like a charm.
Thank you very much
Link | October 16th, 2012 at 12:45 pm
Mysql în paralel cu Percona | Tiberiu Contiu wrote:
[...] http://code.openark.org/blog/mysql/manually-installing-multiple-mysql-instances-on-linux-howto [...]
Link | February 5th, 2013 at 1:37 pm