Weird things happen! Which MySQL server version are you using?
It looks like you managed to start two instances, and from a unix point of view it is no strange. But the problem is that two MySQL instances not only differ for the TCP/IP port number and the Unix Socket file, but there is the data directory, binary log files, server pid, error log file etc, that means that an instance is more related to more installation parameters that to only a port number/socket file configuration. So my humble opinion is that even if it is possible to start multiple instances from a single installation you will possibly experiment some sort of side-effects. I have found an interesting manual page regarding to this: http://dev.mysql.com/doc/refman/5.0/en/multiple-unix-servers.html Let me know! Aloha! Claudio Nanni -----Messaggio originale----- Da: toutiao [mailto:[EMAIL PROTECTED] Inviato: martedì 1 aprile 2008 2.10 A: mysql@lists.mysql.com Oggetto: Re: R: R: Multiple instances howto Nanni, To make things even creepier, I tried to access the 2 "alleged" instances from a different WinXP PC by starting 2 instances of MySQL Administrator, using different port number 33061 and 33062 at the same time. And it worked! I went further to create a database on each instances of MySQL Administrator, test1 and test2. It worked too! The changes are revealed on both instances immediately. I will go ahead to write a LabVIEW test program and try to write to both test1 and test2 alternatively, see how is it work. If so, I will try to configure replication for each "alleged" instances. WHAT IS GOING ON? Jing Zhang toutiao wrote: > > Nanni, > > You know, it's really strange. On 2 different terminals, I ran > > [EMAIL PROTECTED] etc]mysql -S /var/lib/mysql/mysql.sock -u root -p > > AND > > [EMAIL PROTECTED] etc]mysql -S /var/lib/mysql/mysql2.sock -u root -p > > I was able to log in. Then I run "show variables", I could actually see > them listening on different ports (33061 and 33062). If I can start only > ONE mysql instance from the same installation, why am I able to log in 2 > different instances? Where did I do wrong? > > Thanks, > Jing Zhang > > > > > Nanni Claudio wrote: >> >> Jing, >> >> First: you can have only ONE mysql instance running for each >> installation, >> but you can have as many installations as you want on each server. >> So to answer your statement only the first command started mysql, >> while the second command should have given you an error(there is already >> an instance running). >> >> --:Jing:------------------------------------------------------------------- >> And then I started (or, I believe I started) 2 difference instances with: >> [EMAIL PROTECTED] etc]# mysqld_safe --defaults-file=/etc/my1.cnf & >> [EMAIL PROTECTED] etc]# mysqld_safe --defaults-file=/etc/my2.cnf & >> --------------------------------------------------------------------------- >> >> If you issue a 'ps -ef | grep mysql' shell command, you'll see all mysql >> processes running, for each instance you have two basic processes: >> >> ==:ps -ef | grep >> mysql:==================================================== >> mysql5 535 513 6 11:48:56 pts/0 0:01 /.../libexec/mysqld >> basedir=/data/Esercizio/mysql5015 --...... >> >> mysql5 513 367 0 11:48:56 pts/0 0:00 /bin/sh bin/mysqld_safe >> =========================================================================== >> >> The one with the lower id(513) is the one you started, the other(535) is >> the 'son' of 513. >> >> >> Compiling and installing it is surely a good experience. >> What I do NOT like of bundled installations is directory/user sharing. >> If you install it yourself compiling it from sources you can >> choose your directory, user and parameters for a particular mysql >> installation. >> >> My advice is to follow this procedure: >> >> 1) Create a home directory for the user and installation of mysql >> e.g.: /home/mysql5018 >> >> 2) Create a new operating system user for the new installation, >> e.g.: mysql5018, mysql323, etc... >> >> 3) compile mysql (follow the manual) >> >> 4) log on as the new mysql user (e.g.: mysql5018) >> >> 5) install mysql (follow the manual) as that user >> >> 6) create the .my.cnf file and put it in the home directory of the user >> (/home/mysql5018/.my.cnf) >> >> IMPORTANT: watch for right permissions on files and directories. >> >> This way you can start mysql as easy as 'bin/mysqld_safe&' with no >> command line parameters at all, given you are logged as the right mysql >> user(mysql5018) and the .my.cnf is in his home directory. >> >> This is how I got so far. >> >> Aloha! >> >> Claudio Nanni >> >> >> >> -----Messaggio originale----- >> Da: toutiao [mailto:[EMAIL PROTECTED] >> Inviato: sabato 29 marzo 2008 22.05 >> A: mysql@lists.mysql.com >> Oggetto: Re: R: Multiple instances howto >> >> >> Nanni, >> >> Thanks for the advices. How to make an installation? I use Fedora Core 8 >> where MySQL comes with the bundle. Do you think I should download the >> source >> code and compile it and configure it using ./configure? >> >> I did changed the cnf file to have 2 different configurations: >> >> [EMAIL PROTECTED] mysqld]# cat /etc/my1.cnf >> [mysqld] >> port=33061 >> datadir=/var/lib/mysql >> socket=/var/lib/mysql/mysql.sock >> user=mysql >> # Default to using old password format for compatibility with mysql 3.x >> # clients (those using the mysqlclient10 compatibility package). >> old_passwords=1 >> >> [mysqld_safe] >> log-error=/var/log/mysqld.log >> pid-file=/var/run/mysqld/mysqld.pid >> [EMAIL PROTECTED] mysqld]# cat /etc/my2.cnf >> [mysqld] >> port=33602 >> datadir=/var/lib/mysql >> socket=/var/lib/mysql/mysql2.sock >> user=mysql >> # Default to using old password format for compatibility with mysql 3.x >> # clients (those using the mysqlclient10 compatibility package). >> old_passwords=1 >> >> [mysqld_safe] >> log-error=/var/log/mysqld2.log >> pid-file=/var/run/mysqld/mysqld2.pid >> >> >> >> And then I started (or, I believe I started) 2 difference instances with: >> [EMAIL PROTECTED] etc]# mysqld_safe --defaults-file=/etc/my1.cnf & >> [EMAIL PROTECTED] etc]# mysqld_safe --defaults-file=/etc/my2.cnf & >> >> >> I checked the service status: >> [EMAIL PROTECTED] mysqld]# service mysqld status >> mysqld (pid 3542 3403) is running... >> >> Does it means I have two instances running? If I want to configure them >> seperately using mysql command, what shall I do to distinguish each >> instances? >> >> Thanks, >> Jing Zhang >> >> >> >> >> Nanni Claudio wrote: >>> >>> Hi Jing, >>> >>> Logically speaking, >>> you can run as many instances of mysql as you want, >>> but you have to make an installation for each mysql instance. >>> On each instance you can have as many databases as you want. >>> From my experience here is the key: >>> >>> 1) One different mysql user (mysql41,mysql50) for each mysql >>> installation. >>> >>> 2) put .my.cnf file in the home directory of each mysql user with the >>> right parameters. This is the way I have found not to conflict between >>> instances. >>> The socket file is a file name you have to assign to each instance, >>> Use a different name for each instance. >>> >>> :-----.my.cnf------------: >>> # The MySQL server >>> [mysqld] >>> port = 3515 >>> socket = /tmp/mysql5015.sock >>> skip-locking >>> key_buffer = 256M >>> max_allowed_packet = 1M >>> :-------------------------: >>> >>> 3) Of course each mysql instance must bind to a different >>> port(3306,3316,3326) >>> >>> >>> Let me know. >>> >>> Aloha! >>> >>> Claudio Nanni >>> >>> >>> -----Messaggio originale----- >>> Da: toutiao [mailto:[EMAIL PROTECTED] >>> Inviato: venerdì 28 marzo 2008 3.03 >>> A: mysql@lists.mysql.com >>> Oggetto: Re: Multiple instances howto >>> >>> >>> >>> In addition, can you run multiple instances of mysqld simultaneous? >>> >>> >>> >>> toutiao wrote: >>>> >>>> >>>> Dear Friends, >>>> >>>> I'm learning to create multiple mysqld instances on Linux, where one >>>> instance of mysql is already running. >>>> >>>> While creating a new my.cnf file, I noticed that I need to assign a >>>> socket >>>> file to it. >>>> >>>> Can you pls. tell me how to create / test this socket file? >>>> >>>> Thanks, >>>> Jing Zhang >>>> >>>> >>> >>> -- >>> View this message in context: >>> http://www.nabble.com/Multiple-instances-howto-tp16338723p16344323.html >>> Sent from the MySQL - General mailing list archive at Nabble.com. >>> >>> >>> -- >>> MySQL General Mailing List >>> For list archives: http://lists.mysql.com/mysql >>> To unsubscribe: >>> http://lists.mysql.com/[EMAIL PROTECTED] >>> >>> >>> >>> "Questo messaggio ed ogni suo allegato sono confidenziali e possono >>> essere >>> riservati o, comunque, protetti dall'essere diffusi. 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Se il >> ricevente non é il destinatario diretto del presente messaggio, é pregato >> di contattare l'originario mittente e di cancellare questo messaggio ed >> ogni suo allegato dal sistema di posta. Se il ricevente non é il >> destinatario diretto del presente messaggio, sono vietati l'uso, la >> riproduzione e la stampa di questo messaggio e di ogni suo allegato, >> nonché la diffusione del loro contenuto a qualsiasi altro soggetto" >> ***** >> "This message and any attachment are confidential and may be privileged >> or otherwise protected from disclosure. If you are not the intended >> recipient, please contact the sender and delete this message and any >> attachment from your system. If you are not the intended recipient you >> must not use, copy or print this message or attachment or disclose the >> contents to any other person." >> >> -- >> MySQL General Mailing List >> For list archives: http://lists.mysql.com/mysql >> To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED] >> >> >> > > -- View this message in context: http://www.nabble.com/Multiple-instances-howto-tp16338723p16400907.html Sent from the MySQL - General mailing list archive at Nabble.com. -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED] "Questo messaggio ed ogni suo allegato sono confidenziali e possono essere riservati o, comunque, protetti dall'essere diffusi. Se il ricevente non é il destinatario diretto del presente messaggio, é pregato di contattare l'originario mittente e di cancellare questo messaggio ed ogni suo allegato dal sistema di posta. 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