MySQL 5 Master-Master question

Discussion in 'Server Operation' started by tfunky, Jan 4, 2008.

  1. tfunky

    tfunky New Member

    Hi All,

    I'm confused on Master-Master replication vs. a MySql HA cluster...

    Specifically the HA Mysql Cluster Howto and the Mysql5 Master-Master replication on Etch howto.

    I've googled around looking for a definitive anwser on which way to go and I'm not finding anything really concreate other than mysql.com saying that "In some instances, a HA cluster is the perfect solution, but in most other Master-Master replication is the way to go"

    What??? That's just about as clear as mud!

    I currently have 1 mysql server running and would like to be able to add capacity and redundancy.

    In the past I did the MySQL HA Cluster howto with the 2 loadbalancers, etc, but I somehow managed to smoke the database, so I went back to one system.

    I have multiple webservers behind loadbalancers, and the database server supports those servers.

    With all of that said...my basic questions are:
    1. I'm hoping for a definitive direction on Master-Master replication vs HA Cluster'
    2. With a Master-Master replication, do you still need the loadbalancers?
    3. With Master-Master replication do you have a VIP or does each webserver just point to one database server?


    What is the best/easiest to maintain way of getting a scalable and fault tolerant MYsql setup?

    Thanks!

    Tfunky
     
  2. falko

    falko Super Moderator

    I recommend Master-Master replication because it's easier to set up and maintain. The big disadvantage with a MySQL cluster (at least for MySQL 5.0) is that all data is held in the memory. So if there's a power failure, all your data is gone.

    You can let each web server point to one database server. :)
     
  3. tfunky

    tfunky New Member

    Excellent! Whooohooo!

    Would you recommend using a load balancer/VIP incase there is a failure?

    In my head, if each webserver points to 1 database server, then if one of the database servers fails, the LoadBalancers for the website won't know it, and will keep sending people to a "good" webserver, that has a broken backend.

    What do you think is best?
     
  4. falko

    falko Super Moderator

    You could put the webserver and MySQL server on the same node. So if a node goes down, both the webserver and the MySQL server are down, so that all requests will be sent to the healthy node. :)
     

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